PHYSIC, PRACTICE OF.
We feel that it would be unsuitable to occupy the pages of a work like this with an epitome of the Practice of Physic, composed either on such a scientific plan as would adapt it to members of the medical profession, or in such a more popular style as would be requisite were it addressed to general readers. But there are some topics connected with the study and exercise of the medical profession, from a discussion of which general readers may derive, we conceive, both interesting and useful information. In particular, it seems extremely desirable that the public should entertain more accurate notions than generally prevail, as to the nature and extent of the difficulties medical men have to encounter in the exercise of their profession;—difficulties that are in part, no doubt, common to medicine with all other practical sciences; but which must also be attributed in a great measure to the peculiar character of the subject itself. By being better informed with regard to the nature and sources of these difficulties, the public would be better able to judge of the qualifications they ought to look for in those to whom they intrust their health; more reasonable in the expectations they form of the benefits to be derived from medical assistance; and less easily estranged than they are too apt to be, from a just reliance on persons of judgment and skill, by the boastful pretensions of ignorant and possibly uneducated empirics.
When the physician is called to a patient, there are two objects to which his attention is successively directed; first, to ascertain with what disease his patient is affected; and, second, to determine the method of treatment best suited for its cure or alleviation. In the following article we purpose to consider what are the means that the practitioner employs for effecting the first of these objects—for determining in practice what the disease is with which he has to contend; and, in particular, to take a general view of the difficulties he has to encounter in endeavouring to arrive at a correct judgment on this subject.
A knowledge of the disease with which his patient is affected, the medical practitioner can hope to attain only by an accurate observation of the morbid phenomena or symptoms that manifest themselves, combined with or followed up by a careful consideration of the pathological condi-
tions from which his own experience and that of others has shown that the particular group of symptoms under his observation, or a group closely resembling it, may possibly originate. We had occasion in the article MEDICINE, in advertizing to the attempts which have recently been made to undervalue the study of symptoms as compared with that of proximate causes, to point out the necessary connections and dependencies of these two subjects of medical inquiry; and to show that as, on the one hand, a more accurate observation of symptoms leads to greater precision in establishing the proximate causes of diseases, so, on the other hand, a more correct acquaintance with proximate causes leads to the more accurate noting and the more due appreciation of symptoms. But in considering the relations of symptoms and proximate causes, it is necessary to keep in remembrance, that there is a wide diversity in the degree of directness with which different symptoms indicate the morbid condition upon which they ultimately depend. Thus, if the lining membrane of the air-passages be inflamed, or, in other words, if a person be affected with catarrh, or bronchial inflammation, amongst the principal symptoms that will arise will be fever, cough, and expectoration. Now the fever is immediately an affection of the nervous and circulatory systems, liable to occur in a great variety of diseases besides bronchial inflammation. Its occurrence, therefore, warns us of derangement in some part of the economy, but does not lead us to the respiratory organs as the primary seat of this derangement. The cough depends on a preternatural action of certain of the respiratory muscles, and is liable to be excited by a number of different causes capable of calling these muscles into play. It serves in some degree, therefore, to guide us to the primary seat of disease. The altered secretion, again, of which the expectoration consists, is the immediate result of that state of inflammation of the lining membrane of the air-passages, which constitutes the proximate cause of the disease, and serves very materially to guide us to a knowledge both of its locality and of its nature.
In attempting to ascertain, from a consideration of the symptoms that present themselves, what the disease is with which his patient is affected, the conduct of the practitioner will vary according to the more or less inquisitive character of his mind. The empirical practitioner will content him-
self with endeavouring to determine what name the particular group of morbid phenomena or symptoms under his observation bears in systems of nosology; whilst the rational practitioner will aim at forming a judgment, from the consideration of these symptoms, as to the nature of the disease, or, in other words, as to the proximate cause on which it depends, and its immediate seat. Thus, if a patient presents the symptoms of yellowness of the skin and of the conjunctiva of the eye, the alvine evacuations being whitish or clay-coloured, and the urinary of a yellowish red or saffron hue, the empirical practitioner will be satisfied with knowing that he has to do with a case of jaundice, as distinguished from all other nosological diseases; whilst the rational practitioner or dogmatist will push his inquiries with the view of determining, if possible, whether the jaundice, in this particular case, is referrible to some morbid alteration of the structure of the liver itself, to the presence of gall-stones in the gall-ducts, or to the existence of spasm in these canals (morbid conditions or pathological diseases which may all separately or conjointly produce the symptoms that have been enumerated), or, in short, with the view of ascertaining what particular form of jaundice he has to subject to treatment. Both these practitioners must depend upon their observation of the symptoms that present themselves, for attaining the knowledge which they respectively desire. But the rational practitioner, whose object it is to arrive at a knowledge of the particular form of jaundice under consideration, must investigate these symptoms more accurately and minutely than is requisite for him who is content with the general knowledge of the fact, that the disease with which his patient is affected is that which has been termed jaundice. In the investigation of the rationalist, it is obvious, the differences between the objects to be distinguished, viz. the different forms of jaundice, are less apparent, the resemblances of these objects are closer, and their analogies are more striking, than those that exist between the objects of the empiric's comparison, viz. jaundice and other nosological diseases; and, consequently, a nicer and more elaborate analysis is required for their discrimination.
The process of analysis which the scientific medical practitioner has to carry on in his own mind, in endeavouring, from a consideration of the combinations of morbid phenomena or symptoms that present themselves to his observation, to arrive at a knowledge of the nosological disease with which his patient is affected, and of the morbid condition of the economy on which, in the particular instance, this nosological disease may depend, consists of several successive steps. 1st, He has to inquire what is the function, or what are the functions, a morbid affection or derangement of which is indicated by the symptoms observable. 2d, What is the particular process, or what are the particular processes, in the deranged function or functions, that are more immediately indicated as being disturbed. 3d, If several functions be deranged, he has to consider whether these derangements ought to be regarded as separate and independent occurrences, or as being dependent on one another; and if the latter, what is the particular relation subsisting between them in respect of antecedence and consequence. 4th, By these considerations respecting the deranged functions, the practitioner is gradually led to determine in his own mind what is the organ or part of an organ that is primarily and principally affected. And, 5th, having formed his judgment as to what is the organ, part of an organ, or texture affected, he has to consider the manner in which it is affected, or, in other words, what is the nature of its morbid condition; whether the symptoms can be supposed to depend on simple dynamical derangement, or whether they imply the existence of organic alteration of structure (see article PATHOLOGY); and also, what is the particular morbid change in property or in structure that
must be supposed to exist. Under this last head is obviously comprehended the determination of the pathological nature of the disease with which the practitioner has to contend,—the consideration upon which the practice he is to pursue must necessarily be founded.
In each of the steps of this analytic process there is, in respect of a large number of diseases, ample room for mistake, not only in consequence of ignorance on the part of the practitioner, but in consequence also of the defective state of medical knowledge depending on the inherent difficulties of the subjects to which it relates. In whatever stage of the analytic process such mistakes may originate, their ultimate effect must be to lead the practitioner into one or other of two errors: 1st, that of supposing the existence of morbid conditions which do not actually exist; or, 2d, that of overlooking the presence of morbid conditions which do exist.
We shall endeavour, in the following article, to point out, and to illustrate by particular examples, some of the circumstances under which the practitioner is liable to commit such mistakes; or, in other words, in which difficulties and fallacies in diagnosis are liable to arise. Our illustrations shall be drawn chiefly from the writings of some of the most eminent clinical physicians of the present day, in order to obviate any suspicion that the difficulties to which we refer are attributable to the want, on the part of the observer, of an acquaintance with those precepts which the present state of medical science furnishes for the discrimination of diseases from one another, or of skill in applying these precepts to particular examples. In the course of these illustrations it will appear, that not only may the several sources of difficulty and fallacy to be noticed exist separately, but that two or more of them may, in some instances, occur in combination, rendering the determination of the pathological condition or conditions existing in the economy a matter of proportionally greater difficulty.
The first circumstance to which we shall advert is the occasional existence of organic or structural pathological conditions in some of the textures, systems, or organs of the body, without this being indicated by any obvious or characteristic symptom, so that the physician remains entirely ignorant of their existence till it is revealed by examination after death.
Every part of the body, it may be presumed, is destined for the accomplishment of some particular end; and, reciprocally, each phenomenon which the economy exhibits is referrible to the operation of some particular part of the organized frame. It seems natural, therefore, to infer, that a deviation from the healthy structure of any part of the body must produce a determinate and perceptible change in the performance of the corresponding function; and, on the other hand, that where there occurs a deviation from the healthy performance of any of the functions of the economy, this must depend on some change having occurred in the structure of a corresponding part of the body;—in short, that where there is altered function, there must be corresponding alteration of structure; and where there is altered structure, there must be corresponding alteration of function. As general principles, these propositions are unquestionably true; but at the same time they are liable to very numerous and important exceptions. It has elsewhere been shown (PATHOLOGY, GENERAL) that very obvious deviations from the healthy exercise of the function of a part may manifest themselves during life, without its being possible to detect in that part, after death, the minutest deviation from its natural structure. And it is not less fully established, that in a large number of cases there have been found, on the dissection of bodies after death, deviations of parts from their healthy structure, of which no indicatory symptoms, direct or indirect, had presented themselves during life.
"There is no anatomist," as was remarked by Dr Thomas Simson, formerly the distinguished professor of medicine at St Andrews, "who has had opportunity of opening any number of persons carried off without a manifest disease, but who must have had convincing proofs that there are great numbers of preternatural appearances in the body, which, during life, give no sensible disturbances." (Edin. Med. Ess. and Observ. vol. v. p. 616.) "It has been observed," remarks another intelligent author (Dr Crampston, Trans. of the Assoc. Phys. in Ireland, vol. i. p. 1), "by those physicians who are most in the habit of opening bodies, that they sometimes find morbid appearances after death, which they had not expected, even though they had closely attended to the antecedent symptoms."
The circumstances upon which it may depend that a part of the body may be altered in its structure, and yet no deviation from its healthy functions, or from those of the economy generally, be observable, or at least be observed to result from this alteration, are very various. First, The exercise of the function of the particular organ may not be conspicuous to observation. Secondly, We may be ignorant of the purpose which the part serves in the economy, and consequently unable to detect any deviation from the proper exercise of its functions. It seems reasonable to expect that symptoms will be the more readily perceived, and the more characteristic when perceived, in proportion as we are well acquainted with the healthy functions of the organs on a morbid condition of which they depend, and can easily discern the exercise of these functions. And as the functions of those organs, and their several parts, are in general most apparent and best known, which either perform some of the vital motions (that is, of those motions without which life cannot be carried on for more than a very minute space of time), or which furnish some sensible secretions or excretions, so the symptoms resulting from diseased states of such organs must be more easy of detection, and more characteristic, than those symptoms that are connected with organs not similarly circumstanced. Thus, if the organs of respiration are out of order, or if the action of the heart, the spring of the circulation, is disturbed, the symptoms arising from such disorders are more readily perceived, and more easily referred to the organs concerned in their production, than are the symptoms that arise from the diseases of other parts the action of which is not so immediately necessary to life. If the secreting or excreting organs, as the liver or kidneys, fail in their proper offices, the symptoms thence arising are much more evident than those which depend on the derangement of organs that do not secrete any fluid from the blood; and among the organs that secrete a fluid, there will be greater facility in recognising the symptoms connected with those organs the fluid secreted by which is discharged out of the body, than with those organs whose fluid is retained in the body for the performance of some particular purpose; greater facility in recognising the symptoms produced by pathological conditions of the liver or of the kidneys, for example, than in recognising those produced by pathological conditions of the pancreas, though that, too, is a secreting organ, and separates from the blood a large quantity of fluid.1 Dr Monro, in his enumeration of the circumstances which concur in rendering the history of diseases imperfect, has very properly included "the imperfect knowledge we possess of the functions of some of the organs of the body. Thus," adds he, "we do not know whether or not the spleen be diseased, unless it has attained so great a bulk as to be felt by an external examination." (Morbid Ana-
tomy of the Gullet, &c. 1811, Introduction, p. xxx.) "Nul-
lum est viscus in corpore," says Grottanelli, in a work ex-
pressly treating of diseases of the spleen (Splenis Morbi,
p. 78, Florentine, 1821, 8vo), "quod diutius subdole agrotet,
pathologicumque statum, absque manifesto detrimento
servet, quam lien."
Thirdly, The function of the organ may not be essential for the general wellbeing of the economy, as is the case not be-
with the ovary; or it may be of trivial importance in itself, essen-
and exercise little influence on the action of other organs, to life
as is the case with the gall-bladder. "Before there be any
direct evidence of the existence of enlargement of the ovary,
it has generally," says Dr Hamilton, "made a certain pro-
gress; and although there may be some data, from the ap-
pearances in dead bodies, for conjecturing the phenomena
of the early stages of the disease, yet, practically speaking,
a considerable advance must always have taken place be-
fore either the patient or the practitioner can be aware of
its existence." (Pract. Observat. on Subjects relating to
Midwifery, part i. p. 71.) "The gall-bladder," says M.
Andral, "may be filled with calculi, and even with pus;
its parietes may be the seat of different alterations; its
cavity may have diminished in a considerable degree, or
even disappeared; lastly, it may cease to receive bile, in
consequence of the obliteration of the cystic duct, without
there resulting during life, from any of these lesions, the
production of any morbid phenomenon which can lead to
a suspicion of their existence." (Clinique Médicale, tome
iv. p. 492.)
Fourthly, The change which the organ has undergone, from
though apparently considerable in amount, may not be of contin-
a nature to prevent its performing its destined purposes in
the economy. This seems in particular to be the case when
the structural change occurs in a gradual manner, the parts
apparently adapting themselves to their altered
circumstances. "When a compressing cause," observes
M. Cruveilhier, "acts slowly on the brain, this organ ac-
customs itself to the compression, or rather the compressed
portion becomes atrophied; and if this compressed or
atrophied portion is not indispensable to the free exercise
either of the sensory and locomotory functions, or of the
intellectual faculties, the patient and the physician are not
made aware, by any morbid feeling or phenomenon, of the
existence of the cerebral lesion." (Anatomie Pathologique,
folio, livr. viii. pl. i. ii. and iii.) "The very great frequency,"
says Dr Sims, "of collections of serous fluid found in the
ventricles or membranes of the brain, in cases where no
cerebral symptoms were known to have existed, is a sub-
ject of great importance to pathologists and practical phy-
sicians, especially when viewed in reference to the discrimi-
nation and curative treatment of apoplexy and other dis-
eases of the nervous system. There is also a great variety
of other morbid appearances found on dissection of the
brain, in cases where no symptoms, or no symptoms ade-
quate to explain the phenomena (that is, indicative of organic
lesion of this organ), were noticed during life."2 "Cere-
bral diseases," says M. Rostan (Med. Clin. ii. 354), "may
go on without there existing any symptoms to characterize
them. At all times the occurrence of latent diseases has
been acknowledged; there exist fewer of them at present
than formerly; our means of investigation have been mul-
tiplied to such a degree, that many diseases which would
formerly have been overlooked, are in our days easily re-
cognised. Nevertheless there are still affections of organs
which we are surprised to meet with after death, and
which have not produced during life any sign that could
1 See Introduction to A Treatise on Biliary Concretions, by Thomas Cox, M. D. 8vo. Lond. 1787.
2 With the view of attempting to illustrate this subject, Dr Sims has subjoined a table, containing fifty cases of persons who died of various diseases not cerebral, and who manifested no symptoms referrible to the brain, though, on dissection, effusion of fluid and other morbid appearances were found in the brain or membranes. Med. Chir. Trans. xix. 274-5.
have revealed their existence. This point of pathology is truly very obscure, and almost inexplicable. It is very certain that these things happen when the affection has advanced slowly, and has destroyed the organ slowly; it is very certain also that a lesion of very limited extent, that has come on rapidly, gives rise to well-marked phenomena: but this does not alter the fact that, in the first case, an organ which is destroyed continues its functions; and that, in the second, an organ almost unchanged ceases from its functions. How can the functions still go on in the first case? how do they stop in the second? It is therefore very difficult, not to say impossible, to recognise diseases when they are truly latent; and that there are such, is proved by experience."
The secreting glands seem to be capable of undergoing a very great degree of organic change without their secretion being put a stop to, or even sensibly disturbed, so that unless some other symptoms should happen to indicate the affection that exists, it will not be manifested by any deficient exercise of the proper function of the organ. M. Chardel, in his valuable Monograph on Scirrhus Degenerations of the Stomach (Paris, 1808, p. 133), observes, "that the examination of a great number of dead bodies has convinced him, that frequently even the most considerable diseases of the liver occasion no impediment to the secretion of bile. Very large tumours may form in this organ, appearing to occupy the greatest part of its parenchyma, and still the secretion continue." And he particularly refers to a case of hydatid of monstrous size that had formed for itself a cavity in the liver, without the biliary secretion being put a stop to.
The urinary organs furnish us with numerous illustrations of the existence of organic affections, very considerable in their apparent degree, of which in many instances no indicatory symptoms manifest themselves during life, or at least during a considerable period of their existence. There is perhaps no organ of the body in which a greater extent of structural alteration may take place, without affecting, in a very marked degree, the exercise of its function, than the kidney. In some cases the urine has continued to be secreted when, from the progress of a particular form of disease, little more than the mere shells of the two kidneys has seemed to remain. (See Chardel, as above.) In other cases, calculi in considerable number, and of considerable dimensions, exist in the kidney without materially deranging their function, or otherwise betraying their own existence. "So long," says M. Chopart (Malad. des Voies Urinaires, i. 179), "as calculi remain concealed in the kidneys, they give no sensible signs of their presence. They may exist there and increase, without producing uneasiness, and without causing any symptoms that can even excite a suspicion of their existence. We have quoted examples of persons whose kidneys contained calculi which had not occasioned any pain to them. Baglivi found large calculi in the kidneys of two persons who, during life, had never complained in these viscera." To the same effect a more recent writer, Dr. Marcet, in mentioning the symptoms with which calculi lodged in the kidney is generally accompanied, adds, "Yet cases of this kind occur in which these symptoms are scarcely perceptible; it will appear hardly credible, for instance, that the patient from whom the kidney represented in plate i. was taken, died of hydrothorax, at Guy's Hospital, without any symptom having occurred which could lead me to suppose that there was any disease in the urinary organs." (Essay on Calculous Disorders, 2d edit. p. 11.) In the case alluded to, the pelvis of the kidney was much enlarged and distended by a number of calculi closely pressed against each other; and other calculi were contained in the enlarged infundibula.
In the bladder, also, there may, under particular circumstances, exist disease to a considerable extent, without any
indication of its existence being furnished by the attendant symptoms. "In several cases," says Sir Everard Home (Diseases of the Prostate Gland, ii. 239), "in which I have examined the body after death, calculi have been found enclosed in cysts formed between the fasciculi of the muscular coat of the bladder, so as to be entirely excluded from the general cavity, and therefore had not produced any of the common symptoms of stone. I have seen in the same bladder two, three, and even four such cysts, each containing a calculus of the size of a walnut." And, even independently of the existence of such cysts, calculi may, as Mr. Wilson has remarked, "exist in the bladder for years, without producing always those distressing symptoms which render life a burden, and which so frequently occur in this disease." (Lectures on the Urinary Organs, &c. p. 238, 1821.)
Fifth, Some other organ or part may supply the place from its of that which, by a change of structure, has, in whole or in being executed, been rendered incapable of exercising its function. This is especially the case with those glandular organs which are double; for when one of these is morbidly affected, the other not unfrequently performs its function in such a manner as to supply the place of both. "Suppression of urine," says Mr. Howship (Complaints that affect the Secretion and Excretion of the Urine, p. 2), "may be complete or incomplete. The first case is very rare; the second comparatively frequent. An affection that either deranges or destroys the functions of one kidney, may leave the other to the more vigorous performance of its duty; a circumstance most happily calculated to guard the constitution from the ill effects of a disease the complete establishment of which is almost invariably fatal." "What we have said," remarks M. Bouillaud, "of the obscurity of the signs of diseases of the kidneys, is applicable to those of the lesions of the ureters. If these two canals were obliterated simultaneously, fatal consequences would ensue; but this does not happen when one of these organs only is obliterated. From a case which I shall relate, it appears that, in some instances of this kind, the kidney which has its ureter obliterated, has a tendency to become atrophied, whilst the other becomes hypertrophied, as if that it may be able of itself to fulfil the function which it formerly divided with that of the opposite side. I do not affirm, however, that this is in all instances the case." (Journ. Compl. xxxi. 15.)
May we, in this point of view, consider the brain or any portion of it as a double organ; that is to say, may we believe that the corresponding portions of its two hemispheres co-operate in the exercise of a common function, and that this function will continue to be performed without any sensible or considerable impairment, though the part concerned in its exercise is injured or diseased on one side, provided the corresponding part of the opposite hemisphere remains sound? M. Bouillaud (Traité de l'Encéphale, p. 263, 1825), in speaking of the lesions of the intellectual functions which occur in encephalitis, or inflammation of the brain, decidedly adopts this idea, "When one of the hemispheres only is diseased, either in whole or in part, the phenomena purely intellectual continue entire. I have adduced a great number of observations in support of this fact. The slightest reflection, indeed, might have enabled us to anticipate this result. It is obvious that the brain, the organ of the intellectual faculties, being composed of two halves, which are symmetrical and perfectly similar, each of them is equivalent, in what regards the mechanism of intelligence, to the two combined." And M. Lallemand had previously expressed his belief (Rech. Anat. Pathol. sur l'Encéphale, 1820, i. 435), "that when the sound hemisphere of the brain is not compressed by the one which is diseased, it will continue to perform its functions in respect of intelligence, as in respect of voluntary motion and
Physic. sensibility; that the patient will continue to think with a half of his brain, as he continues to see with one eye, and to hear with one ear."
Sometimes one organ may supply, in a mechanical manner, a deficiency or imperfection in its neighbour; and in such a case the existence of the deficiency or imperfection may not be indicated by any apparent disturbance of the action of the organ in which it exists. This happens by no means unfrequently, for example, when an aperture in the stomach, produced by chronic ulceration, is filled up by the adhesion of the liver, the pancreas, or the spleen, to the margins of the ulcer. "I have been often surprised," remarks Dr Pemberton (On the Abdominal Viscera, 3d edit. London, 1814, p. 130), "to find very extensive mischief in the structure of the stomach, without the constitution being sensibly affected by it; that is, provided the mischief was so situated as not to interrupt the passage of the food. I have seen a large scirrhus in the stomach, near the pylorus, with an open cancer in one part of it, which had made its way through the stomach and through the left lobe of the liver, and an adhesion had taken place between the sides of the abscess and the peritoneum; so that, had not the patient been taken off by a disease in the aorta, I have no doubt but that this abscess would have made its way out through the integuments of the abdomen. Still, however, though this must have been a disease of very long standing, the body was but little emaciated, and the patient had never shown any one symptom by which such a disease of the stomach could possibly have been suspected. This single case," adds Dr Pemberton, "is sufficient to point out the infinite difficulty there is to determine the nature of internal diseases."
From unknown reasons. Sixth and lastly, Medical men must confess that, in some instances, they are unable to assign any plausible reason why the diseased organ does not reveal itself by any outward indication of deranged exercise of function. Thus M. Andral has related (Malad. de l'Encéphale, p. 402, 403) some cases in which morbid softening of the brain, variable in its extent and in its seat, produced neither pain of the head nor disorder of the intellect, nor alteration of motion, nor disturbance of the sensations; nothing, in short, occurred during life that could even excite a suspicion of the central part of the nervous system being in any way affected. "As in these cases," remarks this accurate observer, "the softening was seated in different parts of the hemispheres of the brain, the absence of symptoms cannot be explained by the particular seat of the alteration. As to the nature of the alteration, it appeared identical in all the cases. In all, certainly, the softening was uncomplicated with any injection, effusion of blood, or other lesion; but its latency could not reasonably be attributed to this circumstance. Shall we explain it by conditions inherent in the individuals themselves? Shall we remark that they were all exhausted by chronic diseases, which must have blunted the sympathies, and diminished the tendency to re-action? But in many other cases we shall find the existence of the same chronic diseases not in any degree preventing the development of the usual symptoms of softening of the brain. Lastly, shall we refer the circumstance to the advanced age of the persons? This reason would not be more available than the others; for, though one of the patients was an octogenarian, another was only forty-five years of age. Let us here acknowledge, then, our complete ignorance; and, in reference to these facts, to which we find analogous ones in respect of each lesion that occurs, let us recall to mind a principle which cannot be too often repeated, viz. that the alterations of texture which an organ has undergone do not necessarily occasion a derangement of its functions. Thus there are organic lesions without symptoms, as there are symptoms without any appreciable lesion that can account for them."
To those who are engaged in the examination of dead bodies with a view to trace the connection between the symptoms of diseases and the morbid alterations of structure that produce or accompany them, it must obviously be of essential importance to distinguish, in particular cases, those alterations of structure that had existed during life, without giving any outward indication of their existence, from those on which the symptoms that manifested themselves really depended. The observation of some cases in which the coronary arteries of the heart (the vessels by which the substance of this organ is supplied with blood) were found after death to be ossified, in persons who during life had exhibited the symptoms of the painful affection of the chest termed angina pectoris, led some practitioners to conclude that they had detected, in that alteration of structure, the proximate cause of this disease. More extensive observation, however, has shown that ossification of the coronary arteries often exists without the symptoms of angina pectoris, or even without any symptoms whatsoever, manifesting themselves; as it has also shown that the symptoms of angina pectoris may occur in persons whose coronary arteries are sound. In the same way some recent pathologists have endeavoured to establish that asthma depends, in all instances, upon organic disease of the heart; though it seems to be well established, by the researches of accurate observers, that, though asthmatic symptoms and structural affection of the heart are frequently conjoined, every form of organic alteration may exist in the heart without inducing the symptoms of an asthmatic paroxysm; and that in many persons liable to such paroxysms, there exists no alteration in the structure of the heart. "One who would investigate diseases among the dead," as was remarked by an author formerly referred to (Dr Thomas Simson, in the Edin. Med. Ess. and Observ. vol. v. p. 617), "should have a large history before him of what the living can bear without disturbance. If this had been always the qualifications of our dissections, in what different light should our histories of diseased bodies appear. And, in consequence of this, physicians should not have been so far misled in advancing the causes of diseases, and of the death of their patients, as to have placed every irregularity found as the original of the symptoms they had observed in life. A cautious theorist can never be satisfied in his inquiries till he has found out the disorder whence he can deduce all the symptoms that had appeared to him, by easy and natural consequences. A disorder that he observes upon dissection that has no apparent connection with the apparent disorder that happened in the actions of his patient, must be passed by him as foreign to his inquiry, or is only to be left on record to see if others may afterwards find the connection; but till then, such a disorder can never justly be advanced as the cause of any particular disease."
After the preceding view of the circumstances under which an organic or structural morbid affection of some part or other of the body may escape detection, in consequence of its not giving rise to any perceptible alterations in the exercise of the functions of the economy generally, and more particularly of the functions of the part in which it is situated, we come next to consider those sources of difficulty and fallacy in diagnosis, from which it arises, that although morbid phenomena or symptoms do manifest themselves, it is under circumstances calculated to create an uncertainty as to the nature and seat of the pathological condition on which they depend, or even to excite a belief in the existence of morbid conditions very different from those that actually exist.
In the first place, then, groups or trains of symptoms II. arising from different pathological conditions, may be identical, or at least so similar as to render their discrimination exceedingly difficult, if not impossible. In some cases, this similarity or identity in the groups of symptoms
produced by different pathological conditions, is constant, so that the well-informed practitioner is on his guard against the risk of mistake. But, in other instances, a pathological condition usually recognisable by a group or train of symptoms peculiar to itself, assumes appearances foreign to its own habitual or ordinary character, and such as usually accompany some other form of morbid condition, so that the practitioner is taken, as it were, unawares, and exceedingly liable to adopt an erroneous opinion as to the nature of the disease which he is proceeding to treat. From the illustrations to be quoted, it will be seen that when different pathological conditions or proximate causes give rise to the same group or train of symptoms in different persons, they may have their seat in the same organ, or in different organs. In either case it may be that both the morbid conditions are of an organic character, or that the one is organic and the other dynamical.
We shall, in the first place, adduce some examples of organic pathological conditions, differing in nature, but corresponding in seat, which give rise to groups or trains of symptoms so similar, as to render it difficult, if not impossible, to say, during life, with what morbid condition the patient is actually affected. M. Andral, after describing the different morbid alterations of the mucous membrane of the stomach, and of the subjacent textures, that may arise from chronic inflammation (including cancer, according to the view which he takes of the nature of this disease), puts the question, whether the infinitely varied lesions which he has described are each of them marked by a peculiar train of symptoms? "We do not fear," says he, "to answer in the negative. With the exception of some symptoms that are the mechanical result of the obliteration of the cardia or of the pylorus (the two apertures of the stomach) by a tumour, the same phenomena most generally attend during life these so different alterations of form and of structure." (Malad. de l'Abdomen, p. 429.) In speaking of the symptoms of diseases of the liver, the same author says, "they are few in number, often too obscure or too little marked to enable us from a consideration of them always to affirm the existence of an affection of the liver. In other circumstances there is no room for doubt as to the existence of an affection of this organ; but it is very difficult, or even impossible, to determine its nature. For, on the one hand, analogous symptoms are often produced by affections of the liver which present the greatest differences in respect of their anatomical characters; and, on the other hand, we cannot say that in any of these affections we find any particular symptom constantly present." The same principle is applicable to the diseases of the urinary organs. Dr. Marcet, after enumerating the symptoms generally produced by calculi in the kidneys, or by their passage into the bladder, adds (lib. cit. p. 13), "yet the occurrence of these symptoms cannot be considered as an absolute demonstration of the existence of this disease, unless calculi have been actually discharged; since it is well ascertained that symptoms very nearly similar are also sometimes occasioned by mere inflammation of the kidneys, without any concretions being present."
Before pointing out examples of an organic and a dynamical pathological condition of the same organ producing similar or identical groups or trains of symptoms, it may not be amiss to suggest of how much importance it is that the physician should be able to ascertain whether the proximate cause on which the symptoms in a particular case of disease depend, is organic or dynamical, since, according to the conclusion he may form on this point, the general plan and objects of treatment must be very materially influenced. It is in the class of dynamical diseases chiefly that the efforts of the medical art are likely to be of avail. Of organic diseases there is a very large portion in which, though we
may for a time retard their progress, or alleviate the sufferings to which they give rise, we can entertain very little or no rational expectation of effecting a cure. The distinction between an organic and a dynamical disease of the same organ is one, however, which, in practice, it is very far from being at all times easy to make. The existence of an organic disease can, indeed, frequently be ascertained by direct observation, or by what may be called its physical indications or signs, as when it is seated in external parts, or in parts which the practitioner is able to examine by sight or by touch, directly or with the aid of instruments. In this mode of investigation a correct knowledge of the geography of the body, if we may so speak, is obviously essentially necessary. The practitioner must know the ordinary position of each part, its extent and its relations to the other parts in its neighbourhood. He must know in what situations to expect a prominence, and in what a depression; where to expect to find a soft and yielding part, and where a part that is hard and resisting. But even where he is able by direct observation to ascertain the existence of an organic disease, he often derives from this no knowledge of its particular nature, no information, for example, as to whether a tumour is simply inflammatory or scrofulous, whether it is of a mild or of a malignant nature; nor consequently does he obtain any insight into its probable progress: and in a great many of the organic alterations which occur, from the deep and remote situation of the parts which they occupy, as in diseases of the brain, for example, he is not apprized by direct observation, even of their existence. For all that remains to be learned respecting organic diseases, their existence, their nature, and their seat, after the means of investigation deducible from direct observation, or from what we have called their physical indications or signs, have been exhausted, the practitioner must, as for the whole of his knowledge of dynamical diseases, be entirely dependent on the detection of deviations from the regular exercise or performance of the several functions of the body, or of what may be termed the functional indications or signs of diseases. Hence it is obvious of how great importance an accurate knowledge, both of the healthy phenomena of the economy (as embraced in the science of physiology), and of the various modifications which these phenomena are liable to undergo in the state of disease (the branch of general pathology termed Symptomatology, or Semeiotics), must be to the practitioner of physic.
We may now point out some examples of an organic and a dynamical disease of the same organ, producing groups or trains of symptoms apparently identical. In diseases of the brain, the same train of symptoms may arise from an obvious organic alteration, or without any such alteration, and, as it is usually expressed, from mere functional disturbance. "A person previously in perfect health," observes Dr. Abercrombie (On Diseases of the Brain, 3d edition, p. 199, 200), "falls down suddenly, deprived of sense and motion, and dies after lying for some time in a state of coma. We find, on examination, a large coagulum of blood compressing the surface of the brain, or filling its ventricles, and the phenomena of the disease appear to be distinctly accounted for. Another person is cut off with the same symptoms, but nothing is met with except serous effusion in no great quantity in the ventricles, or only on the surface of the brain. A third is seized in the same manner, and dies after lying for a considerable time in a state of coma, from which nothing can rouse him for an instant; and, on the most careful examination, we cannot detect in his brain the smallest deviation from the healthy structure." Here, then, are three cases which, as presenting the same external phenomena, all fall under the same nosological disease, apoplexy; but of which the first may be regarded as depending on an organic, and the last, at least, on a dynamical affection; whilst with regard to the
Physic: second, it may not be easy to determine whether the morbid appearances discovered after death should be regarded as the primary disease, or only as one of its effects.
The stomach may be mentioned as another organ the structural and dynamical affections of which give rise to closely resembling groups or trains of symptoms. "To trace exactly the phenomena of a disease," says M. Char- del (lib. cit. p. 159), "is not always sufficient for convey- ing a proper knowledge of it; it is still necessary to point out any other affections the resemblance of which with the object of our researches might possibly occasion mis- take. This observation is of especial importance in the case of incurable diseases, since, to confound these with other diseases that are susceptible of cure, is to deprive the un- fortunate persons committed to our charge of the assist- ance which they had a right to expect, and to deceive their confidence. No affection," this author proceeds to observe, "simulates so completely scirrhous degenerations of the stomach as spasmodic vomiting, or that arising from an immediate lesion of the principle of life in the nerves of the stomach, from a special sensibility of that viscus."
Of differ- ent organs: In other instances in which different pathological condi- tions or proximate causes give rise to the same group or train of symptoms in different individuals, the different les- ions have their seats in different organs or parts of the body. These organs or parts may be related to one another simply in the way of contiguity or superposition; or there may exist some functional dependence or sympathetic con- nection between them.
related by proximity: The mistakes liable to occur in the judgments of medi- cal men as to the existence or non-existence of aneurysm, furnish an illustration of the similarity that may exist in the morbid phenomena induced by different pathologi- cal conditions of organs or parts in near proximity. "The occurrence of a pulsating tumour in the vicinity of an ar- tery," says Mr Hodgson (Diseases of Arteries and Veins, p. 88), "will induce every cautious surgeon to suspect the existence of an aneurysm. But there are many diseases which, from their situation, or from other circumstances, may assume the symptoms of aneurysms; and in some instances aneurysms assume the appearances of other dis- eases." "The circumstances that characterize the exist- ence of an aneurysm are much more complicated when the disease is situated in the thorax or abdomen, than when it exists in the extremities. Aneurysms in the thorax or ab- domen frequently prove fatal before a knowledge of their existence is confirmed by that evidence which the appear- ance of the tumour externally generally affords; and the viscera with which they are surrounded are subject to a variety of diseases, many of the symptoms of which are common also to aneurysms of the aorta and of its primary ramifications."
If we turn our attention to the diseases of particular or- gans, we shall find ample illustrations of the source of fal- lacy in diagnosis to which we have just alluded. Practition- ers are well aware that a difficulty of breathing or of swal- lowing may arise not only from affections of the organs by which these functions are respectively exercised, but from morbid conditions of one or other of the neighbouring organs or parts, as of the thyroid or bronchial glands, the vertebrae, and the larger blood-vessels; and also, that whilst difficult respiration may be occasioned by morbid conditions of the pharynx and œsophagus (the organs by which deglutition is effected), difficulty of deglutition may arise from morbid con- ditions of the glottis, of the larynx and trachea, and even of the lungs, that is to say, of the organs of respiration. "Aneu-
risms arising from the thoracic aorta," Mr Hodgson has re- marked, "by compressing the trachea and œsophagus, pro- duce great impediments to respiration and deglutition, and are often mistaken for diseases of the lungs, or strictures of the œsophagus." (P. 91.) M. Cruveilhier, in speaking of the diagnosis of inflammation of the larynx, remarks, that "a very serious error, and, at the same time, one very easily committed, is the referring to inflammation of the submucous membrane of this organ the effects of the compression of the trachea by an aneurysm of the arch of the aorta. Nothing resembles more a paroxysm of suffocation produced by laryngitis than the dyspnoea occasioned by the pressure of an aneurysmatic aorta upon the windpipe. I have myself," he adds, "been on the point of committing this error so much the more easily that the individual submitted to my observation was at the same time affected with hoarseness of the voice." (Dict. de Méd. et Chirurgie, xi. 35.)
"As to the symptoms of splenitis," says M. Andral, "their great obscurity depends on several causes; for, 1st, as the functions of the spleen are unknown, their distur- bance cannot reveal its morbid condition in the same way as the disturbance of digestion reveals an affection of the stomach; and, 2dly, the symptoms produced by inflamma- tion of the spleen must be easily confounded with those arising from inflammation in one of the surrounding or- gans, and vice versa." (Diction. de Médecine, art. SPLENITE.) "The symptoms of the diseases of the pancreas," it has been remarked, "are obscure, being for the most part such as belong equally to morbid affections of other parts con- tained within the abdominal cavity. It is, indeed, very sel- dom that we are able to discover pancreatic disease in the living subject." (Dr Carter, art. PANCREAS, in the Cyclop. of Pract. Medic.) "From common experience," remarks another author, "and the evidence of morbid dissection, it may justly be inferred that disease of the pancreas is a rare occurrence; yet the difficulty of ascertaining the con- dition of this organ in the living subject, by any other sym- ptoms than such as are secondarily manifest in the stomach or liver, must render our judgment in many cases uncer- tain, and our practice, doubtless, sometimes erroneous." (Dr Percival, Trans. Assoc. Phys. in Ireland, vol. ii. p. 128.)
We have seen, in respect of the kidneys, the difficulty of distinguishing, by the symptoms that manifest themselves, between the different affections of which these organs may be the seat. But besides this, they also afford proofs of the difficulty of distinguishing between the morbid conditions of a particular organ and those of the parts in its vicinity. "The diseases of parts near to the kidneys," says Cho- part, in reference to the diagnosis of renal calculus (lib. cit. p. 182), "may be accompanied with symptoms closely re- sembling those which manifest themselves in calculous nephritis. Have there not been found, in persons believed to be nephritic, scirrhous, abscesses, and calculi of the pan- creas, or of the mesentery; the spleen scirrhous, displaced and lying upon the kidney; a tumour of the intestines rest- ing on that viscus, &c.? Other facts of the same nature might be adduced in confirmation of the difficulty that ex- exists in judging of the presence of calculi in the kidneys. But if in some cases we cannot arrive at certainty, we may at least have strong presumptions respecting this dis- ease, by combining all the symptoms, and comparing them with one another."
It is proper to be kept in mind, that the resemblance in the symptoms produced by morbid conditions of organs re- lated to one another by proximity, may show itself either in physical or in functional indications. Of resemblance
1 See generalization of the same fact by Dr Cheyne, in the article LARYNGITIS of the Cyclopædia of Practical Medicine; and corroborative cases in the Lond. Med. Gaz. i. 322, and the Edin. Med. Surg. Journ. xliii. 293, the latter by Professor Graham. See case of aneurysm of the aorta, producing symptoms of pneumonia, related by Rostan, Médecine Clin. i. 64; and on the difficulty of diagnosis in internal aneurysms, particularly abdominal, see case by Dr T. E. Beatty, in Dubl. Hosp. Rep. v. 166.
in physical indications, we may take an example from M. Chardel, who, in pointing out certain circumstances under which scirrhous of the stomach may exist without any tumour being perceptible in the epigastric region, suggests (lib. cit. p. 185) that, on the other hand, tumours really existing in some other organ, such as "a prominent liver, an abscess in the posterior cavity of the epiploa, or a swelling of the pancreas, may simulate an induration of the stomach. Tubercular mesenteric glands, when they are in the neighbourhood of the stomach, may easily be taken for a scirrhous of that viscus." And he adds, that "it is possible that the hardness which the muscles of the abdomen, particularly the recti, exhibit in persons in whom they are strong and much exercised, may equally lead into error." Of resemblance in functional indications, we may quote an instance mentioned by Mr Hodgson, who observes that "when an aneurysm arises from the aorta at the root of the celiac artery, it is attended with frequent sickness, more especially after food is taken into the stomach, and by its pressure produces symptoms like those of stricture of the pylorus." (P. 95.)
The reciprocal influence which the different parts of the body exercise upon one another, often throws great difficulty in the way of the practitioner in attempting, in particular instances, to ascertain the seat of disease from a consideration of the symptoms that attend it, seeing that the prominent symptoms may point at organs very different from those which are actually the seat of disease. This influence is sometimes exerted between parts that co-operate in the performance of the same general function, as when vomiting arises in consequence of obstruction of some portion of the intestinal tube; but in other instances it is exerted between parts concerned in the performance of functions essentially distinct, as when headache or palpitation of the heart occur in various derangements of the stomach and bowels. In consequence of this reciprocal dependency of different parts, not merely may a symptom immediately referable to some particular organ depend on an affection of an organ quite distinct from this, but the same symptom may arise from affections of several different and remote organs. Thus, for example, the symptom of cough, the immediate cause of which is known to be the convulsive or rapid contraction of certain respiratory muscles, may occur as a symptom of various affections of the air-passages or lungs; but it may also form a very prominent symptom in diseases having their seat in parts remote from the respiratory organs; and a late French author, M. de Larroque, has published a work professedly treating of cough as a symptom, more or less severe, of certain abdominal diseases. The circumstances just adverted to render it impossible, it may be remarked, to characterize and recognize diseases by one particular prominent symptom. It is only by marking and analysing the concomitant groups of symptoms that we can arrive at a knowledge of the organ which is the primary seat of disease. When a patient complains of headache, for example, the practitioner must judge, from a consideration of the other symptoms by which this uneasy feeling is accompanied, whether it depends on the existence of some pathological condition in the head, the immediate seat of the symptom, or in the organs of digestion, the derangements of which we know to be capable of inducing it sympathetically. In the same way, when the outstanding or prominent symptom is vomiting, it is only by a careful consideration of the concomitant circumstances that we can hope to determine whether it is in the stomach itself, or in some other organ more or less immediately connected with it, that the original seat of mischief is to be found.
"The general signs by which pericarditis may be recognised," says Mr Adams, "are exceedingly equivocal, and much requires to be done by the physician to clear the
obscurity. I have been frequently called upon to examine the bodies of persons supposed to have died of disease of the lungs or liver, and I have found pericarditis the true and single source of death, although during the previous illness the heart was never suspected to be the seat of a fatal affection. I have myself been witness to the treatment of a case of chronic inflammation of the pericardium in a girl aged fourteen, which terminated fatally, and during the whole progress of the disease, phthisis, or rather what was considered hepatic phthisis, was the disease under which this child was supposed to be gradually declining." (Dubl. Hosp. Reports, iv. 360.)
Morbid conditions of the alimentary canal are peculiarly liable to produce disturbance in the functions of some other organs, without betraying their own existence. "Such," says M. Piorry, in an essay on the influences which the stomach exercises on other organs in health and in disease (Journ. Complém. du Dict. des Scien. Méd. xvi. 199), "such is frequently, in diseases of the stomach, the intensity to which the sympathetic lesion of the related organs amounts, that it seems to destroy the primary affection, or at least to cause it to be overlooked. Whilst the patient labouring under such disease experiences only slight uneasiness in the epigastrium, he is tormented by the severest and most intolerable cerebral, muscular, thoracic, and other pains." "The exact appreciation of the nature of the symptoms observed," remarks the same author, "is so much the more difficult on this account, that the organ whose suffering is symptomatic of the lesion of another part becomes itself a new centre of irradiation, which induces, in its turn, secondary irritations or pains. And as there is nothing to prevent these from being, in their turns, new points of departure of physiological influences, there results excessive difficulty in establishing a just diagnosis, in cases so embarrassing." Every one is aware of the influence which the presence of worms in the intestines is generally believed to exercise in producing derangement in the functions of remote organs. "There are few diseases," says M. Andral (Fieures, p. 273-5), "particularly in children, of which worms have not been supposed to be capable of being the cause. Klein has said, 'Nullum tam peregrinum est symptoma, tamque dissimulatum, quod vermes excitare non possint.' We read in authors numerous examples of palsies, comatose attacks, asthma, palpitations of the heart, obstinate coughs, epilepsies, and hysterical convulsions, depending on that cause. Even tetanus has been considered as the result of the presence of worms in the intestinal canal. In the time of Alexander Trallianus, it was said that, when worms passed from the small intestine into the stomach, they gave rise to excruciating cardialgia, to syncope, and that sometimes even they occasioned sudden death. It must be confessed, that observations of this kind become the less frequent as pathological anatomy is more generally and more carefully cultivated. But, in hesitating as to the reality of these extraordinary facts, let us be careful not to deny altogether their possibility. A hemiplegia caused by worms would not appear to us a less credible phenomenon than a palsy succeeding to the introduction of particles of lead into the alimentary passages. Now nothing, unfortunately, is more real and more common than this last species of palsy. The symptoms caused by worms may, besides, be expected to vary much according to their nature, their number, their greater or less mobility and activity of existence, their more or less immediate contact with the mucous membrane, their situation in particular parts of the alimentary canal, the energy of the patient's sympathies, his nervous susceptibility, &c. Amongst physicians, said De Haen, some have made worms play too important a part in the production of diseases; and others have not paid sufficient attention to them."
To the class of cases in which different pathological conditions, having their seats in different organs or parts of the body, give rise to the same group or train of symptoms, may be referred those in which lesions of the central, or cerebro-spinal and ganglionic, portions of the nervous system occasion the development of symptoms in remote organs of the body, similar to those that are produced, or that may be supposed to be produced, in these organs, by morbid lesions of which they are themselves the immediate seats. In many cases, for instance, of local pains or neuralgias, as of neuralgia of the mamma, of the intercostal muscles, and of the arm, there is reason to believe that the pain is not attributable to an affection of the nerves of the parts to which it is referred, but (as Drs Brown, Darwall, Teale, and other authors, have pointed out) is caused by the presence of a primary diseased state in the spinal cord itself, or in its coverings. Although our limits do not allow us to enter fully into the illustration of the doctrine of spinal and ganglionic irritation, as it has been called, we cannot refrain from quoting a very graphic account of the diversity of symptoms manifested in this class of cases, which is given in a paper on diseases simulating acute inflammatory attacks of various important organs, by Mr Torbet, surgeon in Paisley, contained in the forty-fourth volume of the Edinburgh Med. Surg. Jour. p. 375. "Of the diseases in question," says that author, "females frequently before, sometimes after, puberty, are the most usual victims. The individuals are of what is called irritable constitution, a peculiarity moreover distinctly hereditary, and connected more or less with strumous diathesis. The morbid train of neuralgic symptoms is most usually set in operation either by a serious inflammatory or febrile disease, by excessive fatigue, or by injury, as from a heavy lift or severe fall. The severity and variety of diseases to which the individuals appear to be liable, might almost characterize the affection. You are astonished to hear of their violent illnesses, the powerful remedies that are applied, and the rapidity with which they shake off these attacks. In severity their diseases resemble those of no other persons. They are paralytic, blind, speechless, without food, and without sleep, for weeks or months, and yet they do not die. Is the head the organ affected? Then they have headache, of which no words can convey an idea, ending perhaps in insensibility; or there is a heavy weight pressing down their eyelids, a tight bandage compresses, or hammers beat within their heads, bells ring in their ears, vertigo and sickness overpower them, noise and light disturb them. Is the chest affected? Then a sepulchral cough, each fit of which seems to threaten existence, over which medical art seems to possess no control, harasses from morning to night, and night to morning. There is excruciating pain in the chest, especially during the cough, which is perfectly devoid of expectoration. There is a feeling of swelling and choking at the under part of the neck, tremendous palpitation of the heart; the pulse is quick and agitated, but varying greatly with the severity of the cough; and the heart's pulsations seem to occupy the whole left side of the chest. Is the digestive apparatus the seat of disease? Then ensue vomiting without apparent cause; incessant retching for hours, occurring perhaps every day for weeks, without any thing being vomited; no appetite; unquenchable thirst; occasional severe pain in the belly, or muscular cramps; and costiveness alternating with diarrhoea, the stools being unaccountably copious. Are the organs of voluntary motion attacked? Then there are cramps, prickling or numbness, sometimes severe spasms, like tetanus or hydrophobia than any thing else, ending possibly in catalepsy; or paralysis of one or more limbs ensues. Such is an epitome of the symptoms of the more violent cases; but almost endless variety must of necessity occur, according as
the several nervous centres are affected, and their affections modified by individual circumstances. It is precisely from this variety and anomaly of appearances that practical men are apt to be misled. The most marked symptoms are apparently so distant from, and unconnected with, nervous irritation, and are moreover so violent and similar in their character to pure inflammatory diseases, that there is great risk of our chief curative efforts being directed to the appendages and coincidents, instead of attacking the disease itself."
Numerous facts upon record show that a pathological condition existing in the trunk of a nerve may produce symptoms that appear referrible to the organ in which its branches are distributed. "Every part to which a nervous filament can be traced," as is remarked by Sir Benjamin Brodie (Lectures illustrative of certain Local Nervous Affections, p. 2), "may be said to have its corresponding point in the brain or spinal marrow; and an impression made either at its origin, or anywhere in the course of the trunk of a nerve, will produce effects which are rendered manifest where the nerve terminates, at that extremity of it which is most distant from the brain." The experiments of different physiologists had fully established, that when the pneumogastric nerve, or the recurrent branch of this nerve, which goes to the larynx, is divided on each side of the neck, paralysis of the muscles that open the glottis is produced, and, as a consequence of this, the state of stridulous breathing. The knowledge of this fact has been very ingeniously applied by the late Dr Hugh Ley to the explanation of certain affections of respiration occurring as consequences of disease. Thus he conceives that the crowing or croup-like inspiration which is not unfrequently met with in infants, depends primarily, not on a morbid state of the parts constituting the glottis itself, but upon a morbid condition of the pneumogastric and recurrent nerves; and that in very many instances it is connected with a diseased state of the lymphatic glands of the neck, producing pressure upon these nerves. He has endeavoured likewise to show, that the fits of dyspnoea and stridulous breathing, which patients affected with tumours, aneurysms, or other organic diseases at the root of the neck, sometimes experience, as well as the asphyxia by which such persons are not unfrequently cut off, are often attributable, not to any mere physical or organic compression upon the trachea or larger bronchi, but to the diseased masses being so situated as to cause compression, stretching, or more or less complete destruction, of the pneumogastric nerve, or its recurrent laryngeal branch. (On Laryngismus Stridulus.)
But whilst morbid conditions of the central parts of the nervous system frequently give rise to groups or trains of symptoms that seem referrible to distant organs, on the other hand it sometimes happens, as M. Lallemand has remarked, that diseases having their seat elsewhere than in the brain produce phenomena analogous to those occasioned by certain cerebral affections. (Preface, p. 20.) M. Andral relates (Malad. de Poitr. vol. ii. p. 444) a case in which the symptoms that manifested themselves during life were those of inflammation of the membranes of the brain, whilst the morbid appearances found after death were those of acute inflammation of the serous membrane of the heart; and he refers to a case related by M. Rostan, in which there occurred cerebral symptoms, for the explanation of which no other lesion was found than that of inflammation of the investing membrane of the heart. "These two cases," M. Andral remarks (p. 447), "are well calculated to show, that in consequence of individual susceptibilities, there is no organ the lesion of which may not induce the most varied nervous symptoms, so as to produce sympathetically the different morbid states (i. e. nosological diseases) of which we place the seat in the nervous centres and their dependencies. It has been correctly
laid down, that the alimentary canal, when inflamed, re-acts, more frequently than any other organ, upon the brain, and gives rise to the symptoms of inflammation of the membranes or substance of the brain. But it is not less true, as M. Boisseau has already very well shown, that inflammations of other organs may equally produce, by their sympathetic influence on the encephalon, the different groups of symptoms which constitute the ataxic fever of M. Pinel." Dr Latham, too, after remarking that the perplexities with which the diagnosis of the diseases of the pericardium is beset, are more considerable than any belonging to the inflammatory class of diseases in other organs of the body, has mentioned some cases in which the symptoms that manifested themselves during life were those which usually attend inflammation of the brain, whilst, upon examination after death, the brain and its coverings were found in a perfectly healthy and natural state, and the pericardium alone, or conjointly with the substance of the heart, discovered unequivocal marks of acute and recent inflammation. "These cases," Dr Latham continues, "furnish specimens of the enormous difficulties which medical men have sometimes to contend with in the diagnostic part of their art, and they ought to mitigate the censure of those who would judge harshly of our mistakes. Here it is remarkable, first, that a vital organ should sustain an acute inflammation without any symptom whatever immediately referrible to itself, and that organ the heart; and, secondly, that it should impart expressly to another organ, not the mere symptoms of common derangement, but the authentic symptoms of inflammation, and that organ the brain. Diagnosis is necessarily perplexed and baffled where no symptoms whatever are found in the organ really diseased, and none in those with which it is functionally allied, but in some other organ with which it has no known connection, save that they are both parts of the same body. And, further, diagnosis becomes absolutely hopeless when the organ, thus suffering sympathetically, puts forth, not the sign of a mere indefinite ailment, but of a real disease, changing and disorganizing its structure; as when the brain, being perfectly healthy, manifests the signs of acute inflammation, while the heart, being acutely inflamed, gives no evidence of its disease whatever."
Of the cases in which the medical practitioner is misled by the symptoms that present themselves, as to the nature of the malady under which his patient is labouring, this arises, in some, from a local affection producing the symptoms of a constitutional disease, without betraying any marks of its own existence; whilst in other instances, on the contrary, it depends upon a constitutional disease, simulating, or producing the symptoms of a local affection.
A learned journalist, in quoting a case related in Hufeland's Journal by Dr Roeser of Wurtemberg, in which inflammation of the heart had assumed the symptoms of chorea, or St Vitus's dance, has justly remarked, that "the medical practitioner is not unfrequently puzzled by nervous affections taking on the character of serious organic diseases; he should be on his guard against the reverse, dangerous maladies concealed under the mask of nervous disorders." (Johnson's Journal, July 1829.)
"In local diseases," says Sir Everard Home, in his work on Strictures (ii. 13), "it is often difficult, and sometimes impossible, to ascertain whether the constitutional affections that are met with are in reality symptomatic of the local irritation, or belong to some new disease which has been superinduced; and for want of some criterion to guide our judgment in the investigation of diseases, we too often mistake the occasional symptoms for the disease itself, which, from the obscurity of its situation, or its apparent insignificance, is totally neglected." "The constitutional symptoms which belong to a stricture in the urethra," he adds, "have been more frequently mistaken for an original disease, than those of any other local complaint; and
it is only within these few years that this error has been detected." And to the same effect Dr Thomson observes, in his Lectures on Inflammation (p. 105), that "of fevers resembling intermittent, and arising from local diseases, we have examples in the febrile affections which not unfrequently accompany strictures in the urethra. I have repeatedly known," he adds, "these symptoms mistaken for, and treated as, a true intermittent fever."
It is well known that the "new medical doctrine," maintained by M. Broussais, proceeds on the assumption that certain diseases usually regarded as constitutional or essential, that is, as not proceeding from nor depending on any local affection of a particular organ or texture, always result from certain local internal inflammatory affections, though in some instances there may not occur any well-marked symptoms indicative of the existence of such affections. "All the essential fevers of authors," says M. Broussais, "are referrible to gastro-enteritis (inflammation of the stomach, and adjacent part of the intestines), simple or complicated. Medical men have all overlooked this inflammation when unaccompanied by local pain; and even when pains have occurred, they have always been regarded as accidental." (Propositions de Médecine, cxxxix.) It would be out of place to enter here on an exposition of the errors involved in this fundamental principle of the so-called physiological doctrine of medicine; but whatever may be thought of the doctrine which represents all fevers as originating in and referrible to some local inflammatory affection, it must be allowed, that local inflammations occasionally assume the symptoms and course of particular forms of fever, so as to mislead the practitioner in his judgment as to the nature of the disease which he has to treat. "Before entering," says Professor Van Coetsem of Ghent (Recherches Cliniques, &c. p. 91), "on an elaborate discussion as to the diagnostic value of the local symptoms which manifest themselves during the course of acute arachnoiditis (inflammation of the serous membrane of the brain), we have thought it right to fix the attention of the medical public upon a singular modification of this inflammatory affection, of which we have hitherto in vain sought for any notices in the works of the different authors who have described this affection, if we except only Pinel and Morgagni, who relate with astonishment some scattered observations, which they have, as it were, left to their successors to make use of, when, having become more numerous, they might serve as the foundation for a medical doctrine applicable to analogous cases. We mean to say that this terrible inflammation may sometimes simulate the paroxysms of quotidian or tertian intermittent fever. This result, founded directly on observation, is of the highest importance as regards the treatment; for if, unfortunately, the physician deceives himself respecting the nature of the pretended febrile paroxysms, which are observed at the commencement or during the course of the disease, he loses successively all the patients committed to his care." "Resting on the observations of our predecessors, and on those which we have ourselves collected, we think we may affirm, without fear of being taxed with rashness, that there are acute inflammations of the serous system which sometimes affect the periodical form of intermittent fevers; and that, of these, acute arachnoiditis presents, during its course, more frequently than the inflammations of other serous membranes, the periodicity in question." (P. 121.)
It would appear that under peculiar states of the general constitution, the groups or trains of symptoms characteristic of diseases appertaining to particular organs may manifest themselves, though there do not exist in these organs any morbid conditions, pathological states, or proximate causes, such as those upon which the occurrence of these diseases usually depends. Thus, for example, in
certain states of the general constitution, all the symptoms which indicate an apoplectic attack may occur, whilst, from circumstances developing themselves in the progress of the affection, the practitioner has the assurance that no vascular turgescence of the brain, nor serous nor sanguineous effusion, such as genuine apoplexy depends upon, has actually taken place. As illustrative of those states of the general constitution in which such fallacious or simulating diseases occur, we may refer to that induced by the morbid agent which produces ague or intermittent fever, to the gouty habit or diathesis, and to the hysterical.
We shall give a few illustrations of the influence of each of these forms of constitutional disease in inducing phenomena analogous to those of particular local affections; and, first, of ague. Sydenham, in the account he has given of the epidemic diseases which prevailed from the year 1675 to 1680, in speaking of the intermittent fevers of 1678, makes the following observation (Epistola Responsoria, lma, p. 22-3, edit. sec. Londini, 1685; also Works, London, 1742, p. 284, § 34): "Here it is proper to be noticed, that during the first years of this constitution, a very remarkable symptom sometimes succeeded these intermittents; for their paroxysms did not begin with chilliness and shivering, afterwards succeeded by a fever, but the patient was seized with precisely the same symptoms as if he had been affected with true apoplexy, though, however closely it resembled this affection, the ailment was nothing more than the fever itself attacking the head, as was shown by the colour of the urine and other symptoms. Although in a case of this nature all kinds of evacuations seem to be indicated for producing revulsion of the fluids from the brain, as is wont to be done in primary apoplexy, yet these means must be altogether abstained from, as being wholly opposed to the original cause of this symptom, viz. the intermittent fever, and endangering life, as I have myself known. But, on the contrary, we must wait till the paroxysm disappears spontaneously, at which time the bark, if it could not be administered at an earlier period, must be given as soon as possible, and sedulously repeated in the intervals between the paroxysms, till the patient be perfectly recovered."
Dr Morton, in his treatise De Morbis Acutis, Universalibus, published in 1692, has dedicated a chapter to the consideration of the proteiform character of intermittent fever. He observes that intermittent fevers are wont not unfrequently to assume the appearance of several other diseases, some of them of a very acute character. "These diseases yield to the power of bark, the great specific for the cure of ague; and if bark be not administered, they often prove fatal. No one hitherto," he continues, "so far as I know, has treated of this subject, though its investigation seems to me of the greatest importance for the promotion of practical medicine. Among the innumerable symptoms that usually accompany intermittent fevers, there is no one which does not sometimes rise to such a degree of intensity as to bring the life of the patient into immediate danger, whilst at the same time the type of the fever, in its various stages of chill, heat, and sweating, is completely obscured, so that we are not able to detect the existence of the fever by its usual characters. Sometimes it presents itself to the physician under the mask of a fatal chill; sometimes of an unceasing vomiting, of a griping diarrhoea, of cholera morbus, of colic, of periodical hemicrania, of apoplexy, syncope, rheumatism, of universal spasm, pleurisy, peripneumony, pleurodynie, or of some other disease; and though the remedies be administered that are suitable to the particular disease the form of which it assumes, no benefit is obtained from their use, and it is only by the administration of bark that the symptoms are relieved." (Exercitat. i. chap. ix.)
The class of cases to which Sydenham and Morton re-
fer in the passages which we have quoted, have generally been designated as instances of larvated or masked intermittent fever. But they have not at all times been distinguished with sufficient accuracy from other instances of intermittent fever, in which the symptoms of some severe local malady have manifested themselves in complication with, and not to the exclusion of, the ordinary febrile symptoms of ague; a form of disease to which, from its dangerous character, and frequent rapidly fatal termination, the name of pernicious intermittent fever has been given by Torti and other writers on this subject.
That the gouty or arthritic constitution frequently gives rise to phenomena which simulate very accurately the symptoms of local diseases, although the usual proximate causes of these diseases do not exist, the following passages from Musgrave, a very distinguished writer upon gout, may satisfy our readers. "The diagnosis of anomalous arthritic affections," says this author (De Arthritis Anomala, Exonia, 1707, § iii.), "is surrounded by a great many difficulties, and involved in very deep obscurity." "Indeed those anomalous affections which occur without being preceded by any regular paroxysm of gout, imitate so closely the legitimate and well-marked diseases of the parts which they affect, that it may be considered wholly impossible to discriminate between them. If, for example, angina or quinsy occurs in a person previously healthy, and who has never suffered a single paroxysm of gout, nor shown any tendency to it, and no point of difference can be detected between the symptoms of this case and the ordinary ones of genuine angina, who would dream that this affection was dependent on gout? yet that a gouty angina may occur under such circumstances is established by medical experience beyond all possibility of doubt." "With regard to the inward part or trunk of the body," observes Musgrave (lib. cit. § viii.), "anomalous gout most frequently seizes upon the stomach and intestines. Hence arise anorexia, dyspepsia, vomiting; hence colic, dysentery, diarrhoea, and hence sometimes arthritic abscess. Frequently it attacks the head, exhibiting at one time the appearance of vertigo, at another of headache, and at another of arthritic apoplexy. Not unfrequently it makes its attack upon the region of the chest and the organs of respiration, presenting itself under the form of asthma, or of cough, or of hæmoptysis, or of arthritic phthisis. Sometimes it even attacks the fauces, assuming the characters of angina; sometimes the gums, receiving the name of gout in the teeth. Sometimes, in seizing upon the kidneys, it produces the symptoms of calculus, dysuria, and strangury. In fine, it lays hold of the viscera, the membranes, the muscles, the glands, the tendons, the ligaments, perhaps even the bones; so that throughout the whole trunk there can scarcely be found a part which is totally exempt from it." "It is well ascertained," adds this author in another place, "that the affections thus produced by this wandering poison (decio miasmata), simulate most accurately all the diseases to which the parts in which they occur are subject; assume their characters, exhibit even their pathognomonic symptoms, and can in no ways be distinguished from the indigenous diseases by the concurrent diagnostics, but, on the contrary, are in fact frequently confounded with them."
We have mentioned hysteria as another of those states of the general constitution that are liable to give rise to groups or trains of symptoms closely resembling those which are wont to arise from morbid conditions of particular organs. Sydenham, in speaking of hysteria, observes (Works, uti cit. p. 370), that "this disease is not more remarkable for its frequency, than for the numerous forms under which it appears, there being scarcely any diseases with which mankind is afflicted, of which it does not assume the semblance. For, of whatever part of the
body it may take possession, it immediately produces symptoms corresponding to that part, so that unless the physician be a person of judgment and penetration, and of considerable experience in practice, he will be deceived, and suppose these symptoms to arise from some essential disease of this or that particular part, and not from the hysterical affection on which it really depends."
"Among the diseases which Sydenham had observed to be counterfeited by hysteria," says an able writer in Rees' Cyclopædia (art. HYSTERIA), "are apoplexy, which terminates in hemiplegia, and is chiefly seen in lying-in women, after difficult parturition attended with great hemorrhage: the clavus hystericus, or acute pain in one small spot in the head, which is often accompanied by vomiting and palpitation of the heart; this is most frequent in delicate and chlorotic girls: pain in the stomach, cholic, with porraceous vomiting, resembling the iliac passion, terminating in jaundice, and always accompanied by great despondency; chiefly attacking women of lax fibre, who have suffered severe labours from large children: pains in the kidneys and bladder, like fits of the stone, with suppression of urine; occurring in women much debilitated by previous hysterical fits, and in a bad state of health, who are also liable to long-continued vomiting and diarrhoea without pain, discharging green bile. He likewise remarks, that the disease is liable to attack the external parts and muscular flesh, sometimes causing pain, sometimes swelling, in the throat, shoulders, hands, thighs, and legs, more especially in the last, which swelling, however, is to be distinguished from œdema, by being greatest in a morning, by leaving no pit after pressure with the finger, and by commonly affecting only one leg, though its external appearance much resembles that of œdema. But the most severe of those pains is that which affects the back. Sydenham adds, that these pains have this circumstance in common, that they all leave the parts extremely sore and tender, as if they had been severely beaten, so that they cannot bear the touch for some time; and that these pains and other symptoms are all preceded by a death-like coldness of the external parts." (Diss. Epistolaris, edit. sec. Londini, 1685, p. 124, seqq. Works, ut supra cit. p. 370.)
Dr Ferriar, in his essay on the Conversion of Diseases (Med. Hist. and Reflections, ii. 17), in speaking of hysteria, remarks that, "whoever would present us with a good book on the fallacy of symptoms, which is greatly wanted, must be completely master of this unaccountable disease." "I have met," says he, "with several cases of hysterical hæmoptoe, in which the quantity of blood evacuated was very considerable; six or eight ounces were sometimes spit up daily, for a fortnight or three weeks successively. Most of the usual symptoms attended which denote danger in this complaint when it arises from other causes; but the equal, moderate state of the pulse, and the appearance of some degree of the globus hystericus, seemed to determine the nature of the complaint; a conversion, accordingly, soon took place to the ordinary hysterical paroxysm, and no bad consequence followed the hemorrhage from the lungs." "In one case," says the same author, "the bowels were attacked, and the symptoms of enteritis (inflammation of the bowels) were so precisely imitated, as to give much alarm for the patient's safety. I suspected the real nature of the disease from observing that the pulse was soft and full, that the evacuations were natural, and that her spirits were agitated, even to involuntary emotions, by slight causes. This case terminated successfully on the accession of clear hysterical symptoms." "Several years ago, I attended an elderly lady, for a complaint which seemed to vibrate between apoplexy and palsy. After lying for several weeks in a state which afforded little hope of amendment, she saw affected with involuntary sobbing and weeping; the
complaints in her head and limbs were converted into hysterical convulsions, and she recovered completely. It is very common to meet with syncope, or palpitations of the heart and great vessels, accompanied with a soporific depression, or extreme dejection of strength and spirits, and converted, after deep sighing or discharge of tears, into the hysterical paroxysm. In these cases the pulse is sometimes full and regular during the most alarming appearance of sinking; and sometimes variable to such a degree as to exclude all conjecture, excepting that of an hysterical origin." (Pp. 29, 30, 32.) It would be easy to swell to a large amount our quotations illustrative of the great variety of diseases which hysteria occasionally simulates. But we must content ourselves with referring to the account which Dr Marshall Hall has given in his work on Diagnosis (p. 214), of hysterical croup and hysterical pleurodynæ; to some cases of hysteria imitating inflammatory action, paralysis, &c., which are related by Dr Bright in his very valuable Clinical Reports (ii. 452); and to a selection of cases presenting aggravated and irregular forms of hysteria, &c. by Mr Laycock, published in the 134th and subsequent numbers of the Edinburgh Medical and Surgical Journal.
In some cases it is not a single form of disease only of which an hysterical state of the constitution induces the phenomena, but several different forms of disease may be simulated in succession. "When the hysterical disposition is set in motion," says Dr Ferriar (p. 31), "it is not uncommon to find many of the different viscera attacked by it in turns, and the disease peculiar to each counterfeited with much exactness. I have seen symptoms of paralysis, jaundice, palpitation, and nephritis, succeed each other rapidly in the same patient, while some of the characteristic marks of hysteria have been discernible, and where the unity of the disease was proved, by the disappearance of all menacing affections on the approach of regular fits."
It is well known to medical men that there are certain difficulties which possess what is called a specific character, of distinction, which depend on the introduction of a peculiar poison into the system, animal or mineral, such as those of syphilis, and of lead, or on a peculiar state of constitution, sometimes hereditary and sometimes acquired, such as cancer. These diseases, in their general features, resemble affections of a simple or non-specific character. Hence it is not unfrequently a matter of great difficulty, when affections present themselves resembling in their symptoms those which are known to be produced by specific diseases, to determine whether or no there exists in the constitution such a modifying influence as should communicate to these affections a specific character, or whether they be the results of diseased action in a constitution not peculiarly modified. Thus, it is well known how much controversy has arisen among medical men as to the possibility of distinguishing the various symptoms of syphilis from analogous affections occurring independently of the operation of the syphilitic virus. "There is hardly any disorder," says Mr Hunter, "that has more diseases resembling it in all its different forms than the venereal disease." (On the Ven. Dis. p. 380.) In the same way, it is, in many instances, impossible to judge, by the symptoms which present themselves, whether an affection, as of the breast, of the lymphatic glands, of the tongue, &c. ought or ought not to be considered as cancerous; and it is only the melancholy distinction of incurability that ultimately clears up the diagnosis. Again, when lead is introduced into the economy, as it may be in a variety of ways, it is liable to give rise to a certain combination of symptoms which, from the predominance of abdominal pains, and the retraction of the belly, bilious vomitings, and obstinate constipation, with which it is accompanied, is usually designated lead colic. But the symptoms of lead colic, as M. Andral has observed, sometimes manifest themselves in per-
sons who have not been subjected to the influence of any saturnine preparation. (Malad. de l'Abdomen, p. 507.) To the same effect, Dr Graves, in the conclusion of a clinical lecture, published in the Lond. Med. Gaz. for 26th February 1831 (vii. 675-6), has suggested, "that perhaps the following general law will be found applicable to the effects which poisons produce on the constitution, viz. that all poisons give rise to a train of symptoms, constituting a certain disease, of which we may always find a counterpart among those diseases which arise in the system from other causes. Thus, symptoms exactly resembling those of colica pictorum (or lead colic) may occur where no lead has acted on the system; and the remarkable epidemic paralysis of the extremities observed in Paris in 1828 bears a striking resemblance to the paralysis caused by lead. If time permitted me to enter upon this subject," adds Dr Graves, "I think I could succeed in bringing forward examples of morbid states of the system, in which symptoms similar to those arising from mercury, arsenic, narcotic poisons, &c. are produced totally independent of the ingestion of these substances."
The resemblance in the groups or trains of symptoms produced by different pathological conditions, which is liable to embarrass the practitioner, or lead him into error in forming his diagnosis, exists in some instances only during a particular period of the course of the disease, as at its commencement or termination. Thus, for example, a great many diseases, in their incipient stages, exhibit the general characters of fever, without any symptom manifesting itself by which the physician can be enabled to foretell whether, in its progress, the disease will prove to be of the nature of simple fever, or one of the various forms of febrile eruption, or whether an inflammatory affection is about to develop itself in one or other of the internal organs of the body. Unless there happen to be some adventitious circumstances, by which in such cases the judgment can be assisted, as, for example, the presumption afforded by the knowledge of exposure to a specific contagion, the practitioner must wait for a more advanced stage of the malady before he can pronounce with confidence upon its nature. M. Pinel, in noticing some remarkable varieties which mania presents at its first commencement, remarks, that "the extreme intensity of the symptoms may sometimes lead to error, and the name of mania may be given to a malignant or ataxic fever; for, besides that the same causes may equally produce one or other of these diseases, they may also exhibit common characters, violent agitations, furious delirium, alternations of stupor and nervous excitement; sometimes a marked acceleration of the pulse, dryness of the tongue, a pale and exhausted countenance, slight and interrupted sleep, and an entire rejection of all nourishment. The distinction is then difficult to make at the commencement, and it is only by watching the disease for several days that the practitioner can arrive at a positive conclusion." (Sur l'Aliénation Mentale, Paris, 1809, p. 59-60.)
As there is in many instances a close resemblance in the symptoms by which different diseases commence, so also it frequently happens that diseases of different natures, at an advanced stage of their course, give rise to some determinate group of symptoms which mask or conceal those of the primary disease, and themselves assume the prominent character. Thus various organic diseases situated in different organs or parts are liable to induce, at an advanced period of their progress, the state of dropsy; and when the dropsical effusion has once attained a considerable extent, it frequently masks the symptoms of the original disease so much as to render it difficult, if not impossible, to ascertain its nature, from the consideration of the existing symptoms. It would appear, however, from the results of recent clinical observation, that if the practitioner is able to ascertain in what situation the dropsical
effusion commenced, and to trace its progressive extension to other parts of the body, these circumstances of themselves often afford sufficient data for determining in what organ the morbid condition is situated on which the production of the dropsy depends.
So much for the circumstances under which the practitioner may be embarrassed or misled in his judgments respecting the seat and nature of diseases, from resemblances in the group or train of symptoms produced by different pathological conditions. The next source of difficulty and fallacy in the diagnosis of diseases which we propose to illustrate, arises from the fact that the group or train of symptoms produced by a particular pathological condition, or concurrence of pathological conditions, in one individual, may be very different from the group or train of symptoms produced by an apparently identical lesion in another individual. This production of two or more different groups or trains of symptoms in different individuals, by a pathological condition or proximate cause that seems to be identical, may occur, as will appear from the illustrations which we shall adduce, whether the pathological state or lesion be organic or simply dynamical.
The diversity in the group of symptoms attending a particular morbid condition, which misleads a practitioner in his diagnosis, may extend to the whole or greater part of the symptoms, or be confined to one symptom, or to a few only. In the latter case the deviation from the ordinary characters of the disease may consist either in the presence of a symptom or symptoms that do not usually attend the morbid condition which exists, or in the absence of symptoms by which it is usually accompanied. The disease drops, as it were, some of its usual characters, or assumes some that appertain to other diseases. "A disease," says M. Rostan (Méd. Clin. ii. 355), "without being entirely latent, may want many of its characteristic symptoms; and this circumstance must occasion great difficulties in diagnosis. This is of frequent occurrence in cerebral diseases. Thus, when softening of the brain is unattended by precursory symptoms, its diagnosis is of extreme difficulty. "Cerebral haemorrhage," says the same author, "may exhibit precursory symptoms, and cerebral softening want them. How, in such a case, can these two affections be distinguished?" Pain being a symptom to which the attention of the practitioner is always forcibly directed by his patient, much reliance is usually placed on its presence or absence in the diagnosis of diseases, and particularly in discriminating between those which are and those which are not inflammatory. It is far, however, from being an infallible sign. "The signs of the different alterations of which the kidney may be the seat are," observes M. Bouillaud (Journ. Compl. xxxi. 13), "very obscure. All that semeiologists have said on this subject is far from being exactly conformable to observation. We may easily conceive why the diagnosis of affections of the kidney presents so many difficulties, if we reflect, 1st, that the depth at which that organ is situated withdraws it almost entirely from our means of exploration; 2dly, that the disturbance of its functions produces phenomena which may equally be occasioned by different diseases of the bladder and ureters; 3dly, that pain is not a constant accompaniment of renal affections. If we trusted to most pathologists, the most acute pains should be almost inseparable from inflammation of the kidneys. I do not pretend to deny that this may sometimes be the case, but I can affirm that I have met with incontestable traces of nephritis in persons who had not complained of any pain in the region of the kidneys. This absence of pain in the diseases of these organs is, besides, the more easily conceivable, that they are not sensible in the state of health. It may be added, that it is not very uncommon to observe violent pains in the region of the kidneys in persons who are not affected with any disease of these organs."
No circumstance certainly tends more to perplex the medical observer, in attempting to determine, from the consideration of the symptoms that manifest themselves in individual cases, what the disease is which presents itself to his observation, than the great diversity which a disease may exhibit in its phenomena, according to a variety of circumstances not at all times easily appreciable; such as atmospheric influence, individual constitution, or perhaps, mode of treatment. Those diseases that arise from the action of a contagious principle afford us the best opportunity of noticing the great diversities of appearance which the same disease may exhibit in particular epidemics, and as modified by diversity of constitution, mode of treatment, &c. If we compare, for example, the severest and the mildest case of typhus fever, or of smallpox, or scarlet fever, we shall have difficulty in believing that they are instances of the same diseases. Yet, in examining a considerable number of cases of any one of these diseases, we shall be satisfied, that between these extreme points there is a series of intermediate links which exhibit the most gradual transition from the most mild to the most severe.
In the diseases to which we have just alluded, we are unable to detect after death, when it occurs, any structural morbid conditions of the different textures, systems, and organs of the body, as being constantly and necessarily present, so as to justify us in regarding them as the proximate cause of the symptoms that manifest themselves; and this circumstance must no doubt add considerably to our difficulty in determining what are the essential and characteristic symptoms by which we should be able to recognise these diseases under the great diversity of appearances which they present in particular cases. But even in diseases in which we meet with structural alterations on examination after death, and these too having proceeded, in some cases, to a very considerable extent, we often find that there had been great diversity in the groups or trains of symptoms by which, in different individuals, the same structural change had been attended.
The various affections to which the contents of the cavity of the cranium are subject, furnish numerous illustrations of the fact that the same structural morbid condition may be attended in different cases by different groups or trains of symptoms. M. Andral, in his Resumé (Malad. de l'Encéphale, p. 522) of the cases which he has published illustrative of softening of the hemispheres of the brain, observes, "In showing us the softening of the brain under all its forms, both anatomical and symptomatical, the preceding cases have shown us also how far the diagnosis of this affection is from being in all instances easy." "In each of the cases, it is not only that the symptoms are not the same, but that the same symptoms are combined, or succeed each other in the most different ways. Hence there result for one particular anatomical lesion, several forms of disease, which, in a nosological table, might be placed at a great distance from one another. In some cases the nosological disease is what is called an attack of apoplexy, with or without loss of consciousness; in others, it is a so-called ataxic or malignant fever; and in others, again, it is a gradual diminution either of motion only, or of intellect and motion at the same time." To the same purpose Dr Abercrombie remarks, that "when we endeavour to trace the leading symptoms connected with the different forms of organic diseases of the brain (comprehending under that name permanent changes of the cerebral substance itself, and new formations within the head), we do not find any uniformity, by which particular symptoms can be distinctly referred to the various forms of the morbid affections." He afterwards alludes to the extreme difficulty of fixing upon any general principles, or of referring the particular character of the
symptoms to any thing in the seat or nature of the disease. "Tumours, for example, will be found, in one class of cases, unaccompanied by any remarkable symptoms; while, in other cases, tumours in the same situation, and of no larger size, are accompanied by blindness, convulsions, or paralysis. It does not appear that these diversities depend either upon the size of the tumours, or, as far as we know at present, upon their particular structure. But these points remain to be investigated; particularly what diversity of symptoms is connected with the nature of the tumours, and especially with their characters, as being tumours distinct from the cerebral mass, or as being indurations of the substance of the brain itself." (On Diseases of the Brain, third edit. p. 316, 322-3.)
In the viscera of the chest, as well as in those of the Thoracic head, examples are to be met with of the same structural diseases. morbid condition giving rise, in different persons, to different combinations of symptoms in concurrence and succession. Thus, Dr Latham, in illustrating his observation, that one of the common difficulties attending the diagnosis of pericarditis is referrible to the variability of its own symptoms, remarks (Lond. Med. Gazette, iii. 211): "Disease belongs most unequivocally to the heart when pain is immediately referred to it, and when its action is disturbed. And when there is fever withal, it bespeaks the essence of the disease to be inflammatory, and fixes it, almost to a certainty, in the pericardium. But why in the pericardium more than in other parts of the heart? Because it is matter of experience, that, above all others, the pericardium is liable to acute inflammation in an incalculable proportion. But, strange to say, the pericardium may be acutely inflamed, and yet there may be no pain. And the disturbance of the heart's action is so little of one kind in all cases of pericarditis, that no certain mode of disturbance can be relied upon as a diagnostic symptom; and though fever may be present wherever there is pericarditis, there is often, at the same time, inflammation of some other organ, out of which it may arise."
Nor are the viscera of the abdomen more constant in respect of the symptoms by which their several structural pathological conditions are attended, than those of the head and chest. Dr Coe, after describing the ordinary signs of biliary concretions when they are making their way through the ducts, remarks (lib. supra cit. pp. 145-6, 147-8) that these "do not happen precisely alike in all persons, but will be found to vary in different patients, and even in the same person at different times, as well as to the number of the symptoms as the degrees of them, and the order in which they come on. Which variations," he continues, "will arise from several causes (in like manner as we see happens in other diseases), according to the difference of constitutions and other circumstances, and according to the size and shape, and perhaps other properties, of the calculi, as also of the ducts through which they pass. From which variation of the symptoms there sometimes arises an obscurity and uncertainty in judging of particular cases. So that we may have good reason to suspect that the disorder is occasioned by a stone, though we cannot be clear enough to pronounce that it is so; which at other times we can do with sufficient certainty." "As in the more uncommon and less known diseases, some particular cases may be so strong and clear as to be sufficiently obvious, so in some of the most evident diseases, which are readily known at first view when the train of symptoms is regular and uniform, we sometimes meet with so great irregularity, and such a perplexed combination of circumstances, that we are at a loss to unravel them, and find some difficulty in determining the particular nature of the case."
From the illustrations that have been given of the two last-mentioned sources of difficulty and fallacy in diagnosis, it must be obvious that, in practice, they frequently
occur combined with one another. A concurrence of symptoms which we shall designate as A, may arise from two different lesions and ; whilst at the same time the lesion , besides giving rise in one individual or class of individuals to the train of symptoms A, may in another individual give rise to a different train B. When, therefore, A presents itself to our notice, we may suppose it to depend on in cases in which it actually depends on . And when B presents itself to our notice, we may fail to detect its dependence on , from its not occurring to us that this lesion can exist without being attended by the symptoms A. "If inflammation of the contents of the cranium always announces itself by the same symptoms," says M. Charpentier, "or if the symptoms by which it usually announces itself did not sometimes depend solely upon simple irritation reflected upon the brain by some organ or organic texture in a state of inflammation, its diagnosis would never be very difficult. This, however, is not the case, for inflammation of these parts occasionally differs so much from its ordinary physiognomy, both in respect of its course and of its symptoms, that the opening of the dead body can alone reveal its existence; whilst at other times simple sympathetic irritation of the brain deceives so much by the perfect resemblance of its symptoms to those which meningo-cephalitis (inflammation of the membranes and substance of the brain) presents, that the sight of the uninflamed condition of these parts can alone deceive us as to the nature of the disease. Among the number of affections capable of inducing cerebral symptoms which by their concurrence simulate meningo-cephalitis, we must particularly reckon the presence of worms in the intestines, dentition, pneumonia at its height, but, above all, inflammations of the stomach and small intestines." (De la Nature, &c. de la Maladie dite Hydrocéphale Aiguë, Paris, 1829, p. 195.) M. Rostan, in showing that pain, vomiting, and swelling form the principal characters of cancer of the stomach, remarks (Médecine Clinique, ii. 477), "These symptoms, however, may exist, and the disease (that is, the pathological condition of cancer of the stomach) not exist, and vice versa, that is to say, the symptoms may be absent, and yet the disease exist. And, in the first place, pain appertains to all diseases of the stomach, and cannot be regarded as a special sign of that in question; the same may be said of vomiting; and, lastly, swelling may appertain to a multitude of different lesions. Engorgement of the liver, of the spleen, or of the pancreas, the accumulation of fecal matters in the arch of the colon, aneurismal dilatation of the aorta, and other accidental tumours, may so much the more readily pass for cancer of the stomach, that most of them occasion disturbance of the digestive functions. In the second place, the pain may not exist, as happens in cases of indolent cancer, which, as is well known, are not uncommon. The vomiting, also, may not occur, 1st, when the pylorus is free; 2d, when it is extensively ulcerated; 3d, when the whole of the stomach is involved in the disorganization. The swelling may not be sensible, which, so far as regards diagnosis, is the same as if it did not exist, 1st, when the false ribs and sternum descend very low, and cover it; 2d, when the free border of the liver lies over it; 3d, when the subject is pretty stout; 4th, when the abdominal muscles contract," &c. "Notwithstanding these difficulties," adds M. Rostan, "it is in general possible to arrive at a precise diagnosis, because it rarely happens that they occur in sufficient number entirely to mask the disease."
But although a train of symptoms apparently identical may arise from different morbid lesions, and different trains of symptoms may arise from what appears to be an identical lesion, it is possible that in neither case does there actually exist the identity supposed. For, notwithstanding the apparent resemblance of the symptoms arising
from different lesions, it seems reasonable to suspect that there may exist points of difference between these symptoms, if we were capable of detecting them. And, accordingly, the progress of improvement in diagnosis has in numerous instances brought to light symptoms or marks by which we are enabled to distinguish between different morbid lesions of the economy, that had previously been supposed to produce precisely the same trains of symptoms.
Of many nosological diseases, such as asthma, ileus, and jaundice, it may be said that they afford examples of the same group or train of symptoms, arising from different pathological conditions. Asthma, for instance, understanding by that term "difficulty of breathing returning at intervals, with a sense of oppression in the chest and sibilous respiration, cough difficult at the commencement of the paroxysm, or absent, towards the termination free, with mucous expectoration, frequently copious," may proceed from diseases of the respiratory organs, or of the heart and large vessels, or of the organs belonging to the nervous system. But though on a first view it may appear true in respect of each of the nosological diseases that has been mentioned, and of many others that might be enumerated, that different lesions give rise to the same group or train of symptoms, on more accurate examination it will generally be found possible to detect, in the cases which depend on one pathological condition, symptoms that are absent in the cases which depend upon a different pathological condition; or, though the symptoms of the two sets of cases are the same in their general nature, one or more of them may be found to be differently modified. "We must at all times," observes M. Dalmas, "conform to that rule of logic which teaches that one same effect always results from one same cause. If, in cases which have exhibited the same symptoms during life, we meet, after death, with different lesions, we may be sure that the true seat of the disease has escaped our researches. It is proper to remark here, however, that there are some vague words employed in symptomatology to express general results, for which it would be unjust to pretend that, in conformity with the rule alluded to, we ought always to find a single and identical lesion. The words dyspnoea and palsy are so circumstanced. If there be twenty species of dyspnoea, we need not be astonished if we find as many different lesions capable of producing it." It is upon such diversities in the minor features of particular sets of cases, depending on differences of pathological condition, that nosologists found, or should find, their varieties of diseases; and it is by the accurate marking of these diversities that they should seek to improve their systems of definitions.
In like manner, it seems probable, that when different groups or trains of symptoms arise from what appears to be the same morbid lesion, there is in reality some unperceived diversity in the lesion. It may be identical in respect of its nature in the different cases, but different in its seat or in its relations to other parts. For, supposing that in two or more cases the same organ is affected with the same form of disease, it is obvious that there may be considerable difference in the functional disturbance, and consequently in the symptoms that arise, according to the particular part of the organ in which the pathological condition may be seated. In cases of cancer of the stomach, for example, the symptoms vary greatly according as one or other aperture, or the body of the stomach, are affected separately, or in conjunction with one another.
In illustration of the remark, that where the same lesion appears to give rise to different symptoms, there may actually be some difference in the relation of the lesion to other parts, though not adverted to by a superficial observer, we may quote an observation made by M. Cruveilhier in reference to cancerous tumours in the brain. (Anatomie Pa-
thologique, folio.) "A point extremely important in the history of these tumours," says he, "is the difference of the effects produced by causes apparently identical. Thus, in one individual, hemiplegia is occasioned by a spheroidal tumour of two inches in diameter, while in another a tumour of four inches may exist upon the brain without any paralysis being induced, though everything is in other respects correspondent as regards the seat and nature of the disease. I think," adds this intelligent author, "that one of the circumstances to which this diversity of result is attributable is the difference of the direction in which the compressing power acts."
M. Lallemand has with much justice observed, in the preface to his work on Diseases of the Brain (p. xvi.), that "The circumstance which has most influence on the course of symptoms, is the more or less rapid, the more or less slow course of the disease. This influence is such as to cause that very different pathological alterations manifest themselves by phenomena sufficiently similar to deceive the most attentive observer, simply from their corresponding in their general course or progress. Thus, for example, there is more resemblance between the symptoms of an acute inflammation of the brain, and of a softening of the cerebral substance, and those of an apoplexy, or sudden compression of the brain, whatever be its cause, than between the symptoms of an acute inflammation and those of a chronic inflammation of this organ. In the same way, an encysted abscess has less resemblance, in respect of the external phenomena which it produces, to a recent abscess, than to a scrofulous, fibrous, bony, or hydatid tumour, or a foreign body lodged in the brain. The same," he adds, "may be said of the affections of the arachnoid membrane."
"Reason and common sense," observes Dr Latham, "seem to declare, that there cannot be the same disease of the same organ, and yet the most prominent symptoms be absolutely different. But morbid anatomy is not content merely to contemplate a disease in its general character, and have done with it: it takes into account also the various morbid products and changes of structure accompanying it, or resulting from it. In pericarditis it takes cognizance of the lymph deposited upon the surface, and of the fluid effused into the cavity of the pericardium; the different quantities of each in different cases, and the different proportions which they bear to each other. It notices, also, that the lymph sometimes contracts a partial and sometimes a complete adhesion, and sometimes none at all; that the fluid is sometimes freely effused into the pericardium, and envelopes the whole heart; and is sometimes limited by adhesions to a part of it. These conditions must influence the action of the heart in various ways; and morbid anatomy, knowing these things, suggests to clinical observation, with respect to pericarditis, that as its products are different, so too must its symptoms be in different cases, and even in the same case at different periods." (Lond. Med. Gaz. iii. 212.) These observations are well calculated to excite the most minute attention, on the part of medical observers, to the less obvious differences in individual symptoms or groups of symptoms produced by different lesions, and to the less obvious differences in particular lesions which seem to give rise to different symptoms or groups of symptoms.
The last source of difficulty and fallacy which we have to notice as occurring to the medical practitioner, in attempting to judge, from the symptoms that manifest themselves in any particular case, as to the seat and nature of the disease with which his patient is affected, arises from the circumstance, that two or more parts may be the seats of morbid conditions in the same individual at the same time, whether these morbid conditions shall correspond or differ in their nature, and whether they shall have come on simultaneously or in succession. Such a complication of pa-
thological conditions will possibly produce a complication of symptoms which may render it very difficult for the practitioner to ascertain how many parts are disordered, where the principal seat of disorder is, what part was primarily affected, and how far the disorders in the others depend upon that of the part first affected. Thus, if we suppose an individual to be labouring at the same time under the symptoms of disorder of the stomach and of disorder of the heart, the practitioner may experience considerable difficulty in determining whether the symptoms of deranged digestion and those of disordered circulation are referrible to two distinct primary morbid conditions, or whether one or other of these groups of symptoms is not produced sympathetically; whether, whilst one of the groups arises directly from a primary morbid condition of the corresponding organ, as those of indigestion from disease of the stomach, the other group of symptoms, those of disordered circulation, may not depend on sympathy of the heart with the stomach, rather than on a primary morbid condition of the heart itself.
In the case just supposed, the co-existence of two distinct pathological conditions in the economy is obviously accidental, there being no necessary bond of connection between them. But in other instances, from the dependency of different organs and functions upon one another, the existence of diseased action in one organ may occasion diseased action (whether of a simply dynamical or of an organic character) in another. Thus, it is now well established, that in a large proportion of cases of disease of the heart, the change of structure or of action which this organ undergoes is occasioned by an interruption to the circulation of the blood through some other organ of the body, as, for example, through the lungs, in consequence of previous disease of these viscera. Hence, in the progress of cases of this kind, the symptoms belonging to the organ in which the impediment to the circulation exists, come to be complicated with those immediately referrible to the altered condition of the heart, occasioned by that impediment.
The reciprocal dependency of the stomach and liver on one another furnishes us with another example of complication of morbid lesions producing complication of symptoms. "It must be admitted," says Dr Cheyne (Cases of Apoplexy, &c. Lond. 1812, p. 171), "that it is often difficult to know to which viscus of the abdomen we ought to refer the uneasy sensations that attend imperfect digestion. When disease of structure is apparently confined to the liver, the patient has been known to suffer greatly from dyspeptic symptoms (that is, symptoms of derangement of stomach)—great anxiety, sickness, flatulence, and prostration. And, on the contrary, when the stomach alone appears to be the seat of disease, there is not unfrequently an imperfect or redundant secretion of bile (indicating derangement in the action of the liver), with listlessness, depraved sensation, tedium vitæ, &c. The work of the stomach is never well performed unless when the liver is sound, and the functions of the liver equally require a healthy condition of the stomach. As when either viscus is in a diseased state, the uneasy sensations felt in consequence are referrible to both, the stomach and liver are to be considered, in their morbid states, as firmly linked as in health. But in practice it is of consequence to discover in which organ disease has begun; for, if we are able to restore the organ primarily affected, the organs sympathetically drawn into disease will often return to a healthy state in consequence."
The supervision of a new morbid condition in a person previously labouring under some complaint, whether in the same or in a neighbouring organ, is very liable to be overlooked till it has made considerable progress, in consequence of the premonitory and early symptoms being suffocated, as
Physic. it were, in those of the original malady. And if in a case in which there exist two or more distinct pathological conditions at the time of the physician's examination, the morbid phenomena or symptoms produced by one of them be, from the nature or the seat of the organ affected, much more apparent than those produced by the other, then it may very readily happen that the practitioner, having satisfied himself of the existence of the more considerable pathological condition, may take it for granted that this is in itself sufficient to explain all the phenomena that present themselves, and thus fail to detect the existence of the other pathological condition, upon which the less marked, though perhaps not the least important, portion of the symptoms actually depends.
or modifying or obscuring one another. But it is not the mere circumstance of complication, and the difficulty of separating the symptoms arising out of different co-existing pathological conditions, into their respective groups, that render cases of this kind puzzling and perplexing to the practitioner. It frequently happens that the symptoms of one or other, or possibly even of both, the co-existing pathological conditions, are modified in such a degree as to throw over them a great degree of obscurity. "In many diseases," says M. Melier (sur le Diagnostic), "instead of a single organ, or of a single texture, there are two, or a still greater number, affected. It rarely happens, for example, that a mucous membrane is alone affected; it is the same with the skin. It is necessary to attend to this coincidence of several diseases, or rather of several organic foci of disease; for in almost all cases the physiognomy of the symptoms is thereby changed. Two diseases existing in this way together, are far from proceeding as if they existed separately. On the contrary, they modify one another. Sometimes they mutually diminish one another's intensity; at other times one of them, in running through its stages, preserves a preponderating intensity, whilst the other, restrained, so to speak, in its development, advances slowly. The first only attracts attention; but when once it has terminated, the second, which, up to that time, had been slight or unperceived, is awakened, and excites fresh symptoms, which the existence of the other seems to have prevented; as if there were in our economy, as Bichat said on this subject, only a certain amount of strength which cannot exist in excess in one place without being diminished in another, and that nature does not indulge in the development of several diseases at the same time."
"It rarely happens," observes M. Lallemand (p. xix. xx.), "that a patient dies of a simple and single affection. In almost all cases, several organs have been involved simultaneously or successively. Then the symptoms of the one or the other disease predominate; the others are very obscure; and, in all cases, these complications influence one another reciprocally, so as to give an unusual aspect to the concourse of symptoms, and to the progress of the diseases. Formerly, in the examination of dead bodies, attention was paid only to the organ which was supposed to be diseased; and when the alterations did not correspond exactly to the symptoms, medical men were contented with regarding the fact as anomalous; or they supposed they had explained it by attributing it to a peculiar idiosyncrasy; or, better still, they made an abstract being of it, existing by itself, and called it an essential disease. The progress of the different parts of medicine, the exactness that is now bestowed upon the observation of symptoms, and the attention that is given to the examination of dead bodies, enables us to appreciate more accurately than was possible till recent times, the influence of each of these complications on the course and concourse of the symptoms."
In some instances the co-existing pathological conditions, each of which furnishes its particular symptoms to the resulting concourse, are seated in the same organ, or in
textures immediately adjacent; as in the investing membranes of parenchymatous organs. "Next to those diseases of the brain," observes M. Rostan (Méd. Clin. ii. 355-6), "which do not exhibit any symptom, or what are called latent diseases, there are none more obscure than those which are complicated with one another. Thus, when there exist at the same time several different alterations of the brain, as hæmorrhage and primary or consecutive softening, it is almost impossible accurately to determine the nature of the affection; but as in general we recognise at least one of the alterations, these cases cannot rigorously be regarded as errors." M. Lallemand, in remarking that the pathological alterations of the brain are not always accompanied with the same symptoms, and in pointing out that "this apparent disagreement depends sometimes on the different seat of the affection, sometimes on the age, sometimes on the sex, or on the temperament of the patient; sometimes on important complications; and, lastly, at other times on the acute or chronic course of the disease;" adds, "when we compare together cases of affection of the brain and of the arachnoid membrane, exempt as much as possible from complication, we see that they exhibit symptoms very distinct, a particular character (cachet); whilst those cases that are complicated, as is most frequently the case, present a mixture of the two orders of symptoms, a circumstance which has not been sufficiently attended to, and which has frequently led observers into error." (Preface, p. xvi.) The same observation has been specially applied by Professor Van Coetsem to the complication of one particular form of cerebral disease, viz. softening, with inflammation of the arachnoid or serous membrane of the brain. "One of the causes," says this author (lib. cit. p. 374), "which seems to us to render the diagnosis of cerebral softening so obscure, is the complication of arachnitis (inflammation of the serous membrane of the brain), sometimes of an acute and sometimes of a chronic character, which frequently accompanies or precedes the morbid degeneration of the substance of the encephalon, and in other instances succeeds to it. In fact, it has more than once happened to us, after conceiving that we had recognised the nature and the seat of the disease by its symptoms, to find in the bodies of those who have died, independently of the lesion of the substance of the brain, which we expected, unequivocal traces of inflammation of the serous membrane that surrounds this viscus, such as adhesion between the different laminae of the arachnoid, sero-purulent effusion into the lateral ventricles, &c. In such circumstances the facies morbi appears to us very doubtful, in respect of diagnosis, because the symptoms connected with each of the co-existing affections are far from being characteristic."
In other instances the different pathological conditions which exist simultaneously have their seats in distant organs. When one of these organs is the brain, the symptoms that might be expected to arise from the diseased condition of the other organ are exceedingly liable to be obscured. "The diseases of the brain," says M. Bourdon (Principes de Physiologie Médicale, i. 164), mask the diseases of other organs. Far from requiring opium, cerebral affections serve as such to the whole body." M. Lallemand, in speaking of the influence of cerebral affections on the development of the symptoms of such diseases as may exist simultaneously with them, observes (i. 233), "Whenever the functions of the brain are disturbed, and there exists at the same time an inflammation in some other organ, the pain produced by that inflammation diminishes, and even entirely disappears." "It is not," he adds, "because the pain of the head is greater, that that of the abdomen or of the chest, &c. disappears, for frequently there is no headache in these cases. Nor is it because the inflammation in the brain is more severe, seeing that an effusion of serum or blood may produce the same effect; it is because the pain being
the result of a sensation perceived by the brain, whatever deranges its functions will cause this symptom of the inflammation to disappear. But if the inflammation is severe, it is not arrested in its development by the cerebral affection; all the other phenomena continue, because they are not, like the sensibility, dependent on the brain. The disease runs through its course in a manner so much the more dangerous, as it is the more difficult to be recognised, and produces the death which is attributed to the affection of the brain, though this be in reality only accessory. If the body be opened with some attention, we are surprised to find so little relation between the symptoms observed during life and the morbid alterations found after death; and this misapprehension throws discredit on medicine, and on pathological anatomy in particular. It is, therefore, of the greatest importance, whenever we observe any symptom which indicates an alteration in the functions of the brain, not to allow ourselves to be imposed upon by the absence of pain. We must then investigate with so much the greater attention the other phenomena, which, being independent of sensibility and volition, do not vary with the state of the brain. "These proper symptoms are so much the more precious, that, if alterations of the brain mask, so to speak, certain inflammations of the stomach, by causing the disappearance of the pain, it also happens very frequently, by a singular sort of compensation, as it were, that certain cerebral affections produce sympathetically nausea and obstinate vomiting, which might be regarded as symptoms of inflammation of the stomach." "These considerations on the perception of pain apply to all inflammations complicated with cerebral affection."
The influence of delirium in concealing the symptoms of diseases seated in other organs than the brain must be explained upon the same principles. In reference to a case of fever in which, as appeared on examination after death, there occurred perforation of the small intestine, followed by inflammation of the serous membrane of the abdomen, but in which the usual symptoms of these morbid conditions did not manifest themselves, M. Louis takes occasion to observe, that "the most formidable symptoms are usually so completely masked by delirium, that as soon as it declares itself, the diagnosis of diseases that are most easily recognised becomes difficult, and sometimes even impossible." (Recherches Anatom. Pathologiques, p. 187.)
In treating of "ramollissement (softening) of the central parts of the brain, combined with serous effusion," Dr Abercrombie remarks, "an interesting modification of this affection is that which supervenes upon other diseases, chiefly of a chronic nature, especially affections of the lungs; and the remarkable circumstance in these cases is, that the pectoral symptoms generally cease after the commencement of the symptoms in the head." (On the Brain, 3d edit. p. 137.)
M. Andral, in speaking of the varieties of pneumonia, or inflammation of the substance of the lungs, observes (Malad. de Poitrine, i. 369), that some very important modifications of this disease depend on the absence of one or of several of its usual symptoms, whence results latent pneumonia. "It is well established," he continues, "that an intense inflammation of the parenchyma of the lungs may exist without being announced by dyspnoea, cough, or expectoration. It may sometimes happen, even, that at the same time that these symptoms are wanting, auscultation and percussion themselves cease to reveal the true state of the lung; in this case it becomes impossible to establish a diagnosis. We have already remarked that these latent pneumonias are rarely primary, but generally supervene when an inflammation of the lung complicates some other disease." "We have seen," remarks the same author (Fieures, p. 441), "in recapitulating the lesions dis-
covered by opening the bodies of the dead, that in severe fevers pneumonia was a very frequent complication, and most frequently a fatal one. If we pass in review the symptoms which have announced this inflammatory affection, we shall find that, in most of the cases, the diagnosis has been very obscure. These intercurrent pneumonic affections have frequently not been announced by any apparent oppression of respiration, nor by any characteristic expectoration. The cough itself was very slight, and the disorganization of the lung might be completed before even any suspicion of the existence of pulmonary inflammation was excited. Hence the indispensable necessity of frequently practising percussion and auscultation in such cases. Lastly, we have seen these two modes of investigation become themselves useless, when the inflammation was settled in the centre, the base, or roots, of the lungs. The absence of all characteristic expectoration in these cases of intercurrent pneumonia may often depend on the circumstance that the patients, having reached the last degree of debility, swallow their expectoration, when they have no longer the strength or instinct to spit it out. But sometimes also it appears that there is really no secretion, and this seems to occur particularly in cases of splenisation, or pultaceous softening of the lungs."
We have thus endeavoured to illustrate the various circumstances under which it may happen that, in the examination of a patient, a well-informed medical practitioner may fail to detect the existence of any morbid or pathological condition of the economy, though such a condition actually exists; or, in recognising the existence of some such condition, may form an incorrect judgment respecting its nature or its seat. These sources of error in diagnosis we have attempted to reduce to four general heads, which may be shortly stated in the following terms: 1st, Morbid lesions without symptoms; 2d, identical symptoms with different lesions; 3d, different symptoms with identical lesions; and, 4th, complications of lesions and symptoms.
We have seen, in the first place, that many changes may take place in the structure of the different textures, systems, and organs of the body, and that even to a considerable degree, without producing any symptoms which attract the notice of the individual himself, or of his medical attendant, in the event of some other ailment giving occasion to the latter to inquire into his patient's state of health; or, at all events, without producing any symptoms calculated to direct attention to the organ or part in which the change has occurred. The causes that may be assigned for this occasional latency of morbid lesions we have endeavoured to refer to the following heads: 1st, The lesion being seated in an organ the function of which is not exercised in a conspicuous manner; 2d, its being seated in an organ, of the function performed by which we are ignorant; 3d, its being seated in an organ that is not essential to the wellbeing of the economy, or that is of trivial importance; 4th, the exercise of the function not being prevented by the change that has taken place in the structure of the organ, as happens particularly when the alteration is slow in its progress; and, 5th, some other organ exercising the function or supplying the place of that which is injured. We found it necessary to admit, also, that in some instances no explanation of the latency of the morbid lesion can be given; and we may remark, that in explaining the same particular instance of latency, we may sometimes find it necessary to refer it to two or more of the causes which we have mentioned, operating in conjunction.
We have seen, in the second place, that a particular, and, to all appearance, identical group or train of symptoms, which in one individual is connected with one form of pathological condition, may, in another individual, be con-
Physical nature. We have seen, that when different pathological conditions or proximate causes give rise to the same group or train of symptoms in different persons, these lesions may be both organic, or the one lesion may be organic and the other dynamical. In some instances the different lesions giving rise to the same group or train of symptoms have their seats in the same organ; in other instances they are seated in different organs or parts of the body, and these different organs or parts may be related to one another simply in the way of contiguity or superposition, or there may exist functional dependencies or sympathetic connections between them. To this head we have referred the class of cases in which lesions of the central portions of the nervous system give rise to symptoms in particular organs of the body similar to those that are produced, or that may be supposed to be produced, by lesions of which these organs are themselves the immediate seats; and that other class of cases in which a central portion of the nervous system exhibits symptoms of being affected with some morbid condition, while in fact it is in some other organ that the primary source of disturbance is seated. We had occasion to observe, that in some of the cases in which one disease assumes the characters that usually appertain to another, it is a constitutional disease which assumes the appearance of a local one; and that in other instances, again, it is a local disease which assumes the semblance of one that is constitutional. Sometimes the simulating disease retains one constant character throughout its progress, while in other instances it assumes in succession a variety of different characters. We have seen that the characters by which certain specific diseases can be distinguished from analogous diseases that are destitute of a specific character, are often far from being obvious, and that consequently the discrimination of these two classes of diseases is frequently a matter of difficulty and uncertainty. We have seen, likewise, that in some cases the community of symptoms between two diseases may exist only during a particular period of their progress, as at their commencement or termination; and that in other cases the community of symptoms may continue during their whole progress.
In the third place, we have seen that different groups or trains of symptoms may arise, in different individuals, from pathological conditions or proximate causes that appear to be identical. This seems to occur whether the pathological state or lesion be simply dynamical or organic. We have seen that the diversity in the group or train of symptoms may be confined to one of the symptoms, or to a few only, or may extend to the greater part or to the whole of them; and that it may consist in the presence of a symptom or symptoms not usually attendant upon the morbid condition, or in the absence of a symptom or symptoms by which it is usually accompanied. Under this head we have illustrated, or rather suggested, the influence of external and internal circumstances in modifying the characters which the same disease exhibits in different persons.
In relation to these two last-mentioned sources of difficulty and fallacy in diagnosis, we have seen reason to suspect that when groups or trains of symptoms apparently identical arise from different morbid lesions, and different groups or trains of symptoms arise from what appears to be an identical lesion, it is possible that in neither case does there actually exist the identity supposed; but that the apparent identity is attributable only to our inaccurate observation, or to the imperfection of the means of investigation hitherto ascertained.
Fourth and lastly, we have seen that several different pathological conditions, having their seats in the same or contiguous organs or parts, or in organs or parts remote
from one another, may exist in the economy simultaneously, whether they shall have come on simultaneously, or shall have followed one another in succession; and, in the latter case, whether they shall stand in the relation of cause and effect, or shall be entirely independent of one another; and that not only may these co-existing pathological conditions, in producing in a more or less marked manner their respective symptoms, give rise to a complication of phenomena which in many instances it is by no means easy to unravel, but they may in various ways modify and obscure the phenomena appertaining to one another.
In illustrating these several sources of difficulty and fallacy in diagnosis separately, it has very clearly appeared, that in a large number of cases they are met with, not singly, but more or fewer in conjunction; a circumstance which cannot fail seriously to increase the embarrassments of the practitioner. Had our space allowed of it, it was our wish, with a view to impress more forcibly on our readers the practical operation of these sources of difficulty in ascertaining and distinguishing diseases, to have traced their influence, separately or variously combined, in rendering difficult and obscure the diagnosis of some one particular disease. For that purpose we had made choice of pulmonary consumption; and it is on this account that, in illustrating the several sources of difficulty individually, we have not taken advantage of the numerous illustrations of these which consumption affords, and which have been so ably pointed out in the writings of Laennec, Andral, Louis, Abercrombie, Craigie, and Clark.
With this recapitulation we must bring to a close our review of the various sources from which those difficulties proceed that the medical practitioner has to encounter, either in detecting the presence of disease in the human economy, or, when its existence is manifestly proclaimed by obvious signs, in discriminating, in individual cases as they present themselves to his observation, the true nature and seat of the affection. To the professional reader, we flatter ourselves, such a review may be not without its use, as tending to bring before him, under somewhat of a systematic arrangement, a number of particular facts, of which, in order to avoid the risk of perpetual errors of diagnosis, it is necessary not only that he should be aware, but that he should be able, in the exercise of his art, readily to recall the recollection, and make the appropriate application. On the general reader, we venture to hope, a knowledge of the nature and extent of these difficulties may tend to impress, first, the importance of the friends and attendants of the sick, as well as the sick themselves, not only facilitating such inquiries as the medical practitioner may himself institute, but spontaneously affording every information from which it can be supposed that he may possibly derive aid in forming a judgment respecting the disease under which his patient labours; secondly, the inexpediency of urging the medical practitioner to the precipitate expression of an opinion respecting the nature of his patient's malady, which, however incorrect it may be, must, when once it has been pronounced, enlist upon its side both his pride and his interests, and thus render it difficult for him to perceive the true posture of affairs, and even more difficult for him, perhaps, to avow it when perceived; and, thirdly, the unreasonableness of withdrawing confidence from a practitioner of whose knowledge and skill they have had manifold personal experience, or sufficient warrant on the testimony of others, because in some particular case or cases the judgments which he has formed may have proved to be incorrect. It has been justly remarked, that "in the practice of physic, there is doubtless a great difference in men as to quickness of apprehension, and also as to the improvement derived from experience; so that one practitioner may discover a difficult case much sooner than another. But there is also a difference in respect of cases.
Some are obvious and easy to proper judges at first view; others are so obscure and perplexed that they are not to be hit off at first sight, nor to be discovered by a superficial inquiry, but require time and attention, with a careful discriminating examination of all the circumstances of the patient, before the true state of them can be determined. Some that are not knowable in their beginning, will become evident in their progress or maturity; and it must be owned there are some that will be too hard for all our inquiry and consideration, and cannot be fully discovered but by the anatomical knife after the death of the patient." (Dr Coe, lib. cit. p. 5, 6.)
As a knowledge of the existence of these difficulties seems calculated to bespeak from the public a more favourable consideration for the practitioner who has availed himself of all those means which medical science affords for improving his acquaintance with diseases and his means of discriminating them, so we cannot but think that there is another purpose to which it may, in some degree, also be subservient. We have already expressed our conviction (art. MEDICINE), that it is vain to trust to any legislative enactments for the suppression of quackery; and that the only mode in which any one can hope to promote this end, is by assisting in opening the eyes of the public to the grossness of the delusions which, in matters relating to medicine, they practise upon themselves, or allow others to practise upon them. But if it be admitted that a knowledge of the nature of the disease under which a patient labours, is an indispensable preliminary to the safe and proper management of his case; and if, in attempting to arrive at this knowledge, so many sources of difficulty and fallacy await even the best-informed medical practitioner,—him who is furnished with all the means of avoiding and overcoming them which the accumulated experience of ages has been able to discover or invent,—the prudent man may hesitate before he admits the belief that these difficulties can be overcome by persons of no scientific instruction, and who professedly reject all aid from the observations or experience of others; he may well pause to consider whether the discrimination of such a person can be with safety relied upon, even in those cases of which Dr Coe speaks as "obvious and easy to proper judges," far less in these obscure and perplexed cases, which require so much skilled observation "before the true state of them can be determined;" and whether the freedom of such a person, from doubt or uncertainty in diagnosis, may not arise from the rash presumptuousness of ignorance, rather than from the reasonable confidence which knowledge is calculated to inspire.
We could have wished, before terminating this article, to have taken a view of the means by which the medical practitioner endeavours to overcome those difficulties, and avoid those fallacies of diagnosis, which we have represented as arising from the uncertain relations that subsist between internal morbid conditions of the economy and their external manifestations or symptoms. The observations we can offer on this subject must necessarily be very brief and imperfect; but we are unwilling to leave on the minds of our readers the impression that medical science has accomplished, and can be expected to accomplish, nothing towards the more accurate determination and marking of these relations, which can aid the practitioner in his diagnostic judgments.
Previously to entering on these observations, however, we would repeat, what we have already hinted, that diligence in seeking out, and precision in examining, the symptoms of diseases, are often of themselves sufficient for the correction of those errors into which a less diligent investigation and less precise examination of these phenomena would be liable to lead the practitioner. "There is probably," as Mr Hunter has remarked in his work on the Ve-
neral Disease, p. 379, "no one disease to which some other may not bear a strong resemblance in some of its appearances or symptoms, whereby they may be mistaken for each other. But diseases which resemble others seldom do it in more than one or two of the symptoms; therefore, whenever the nature of the disease is suspected, the whole of the symptoms should be well investigated, to see whether it agrees in all of them with the disease it is suspected to be, or only in part." The judicious remarks applied by Dr Southwood Smith to the symptoms which, in the progress of fever, indicate the occurrence of morbid changes within the abdomen, are applicable, probably, to many other cases of disease. "Their great peculiarity," says he, "which it is as important to know as it is to understand their indication itself, is their want of prominence. They are always to be discerned, or with extremely rare exceptions; but they seldom or never force themselves upon the notice of the careless, or extort the attention of the unobserving: still they are not the less constant in their occurrence because they come without noise, nor is the indication they give of their presence less significant because it is unobtrusive." (P. 288.)
Some physicians, indeed, as we had elsewhere occasion to remark (MEDICINE), have been so much impressed with the fallacies to which those judgments are exposed which medical men form respecting the nature of diseases, from a consideration of their symptoms, that they have gone the length of representing symptoms as of no assistance in diagnosis. "It is not, then, on the symptoms," says a late French writer, "that the diagnosis of diseases must be founded. In order to recognise them, we must go farther back, to their source, and discover the internal and concealed spring which has been the primum mobile of the derangements that appear externally. We must investigate the organic lesion which has produced, which keeps up, and renews the symptoms observed. It is this lesion which constitutes the disease; it is it which has induced the disturbance of the functions." "In diagnosis," says the same author, "we must absolutely direct our attention to the organs, and in no degree to the symptoms." Of the propriety of endeavouring to arrive at a knowledge of the pathological state, morbid condition, or proximate cause on which a disease or particular case of disease depends, and of the curative efforts of the practitioner being directed against that pathological condition when it can be ascertained, and not against one or other of the various symptoms to which it gives rise, no doubt can be entertained; but it must never be forgotten, that it is only by an attentive investigation of the symptoms that we can hope during life to arrive at a knowledge of the pathological condition which exists. And it would be easy to adduce, from the same author who speaks of excluding symptoms from our attention in diagnosis, passages fully displaying the incorrectness of these views, or rather showing that the expressions in which they are clothed greatly belie the meaning they were intended to convey. To escape the fallacies into which symptoms are apt to lead us in our conclusions respecting the pathological conditions upon which they depend, we must study them in all their varieties of appearances and combinations. The doctrine of symptoms is in every respect as improvable as any other department of medical science. By the successive labours of medical men, additions are constantly making to the number of symptoms or indications by which we are enabled to arrive at a knowledge of the existence of disease, and of its particular nature and seat. And with regard to those symptoms that have been long familiar to medical practitioners, and constantly employed in characterizing and discriminating diseases, much has been done, and much is doing, in the way of determining more accurately their connection with particular pathological condi-
Physic. tions of the economy; so that not only are the means which medical men possess of discriminating diseases, through the medium of symptoms, becoming gradually more numerous, but they are also becoming more valuable.
But when the symptoms actually present are insufficient to guide the practitioner to a satisfactory judgment respecting the nature of the disease before him, are there any subsidiary aids towards the accomplishment of this object, of which he may avail himself?
Previous history of the case. In the first place, a careful consideration of the previous history of the case, from the earliest development of morbid phenomena to the period of examination, may often afford important assistance. For even in cases in which there exists a striking coincidence between the symptoms produced by two distinct lesions at a particular stage of the progress of one or other of them, there may be such differences either in the concurrence of their symptoms at other periods, or in their general course, as to enable the practitioner who is duly informed respecting these particulars to decide on which of the lesions the case under his immediate observation depends.
Causes producing it. In the second place, when, after the most careful consideration of the symptoms as they actually exist, and of the course which the disease has run previous to the time of examination, the nature of the malady is still doubtful, the practitioner may in some instances be assisted in its determination by the knowledge he obtains of the causes by which it has seemed to be induced.
Effects of remedies. In the third place, it happens in some cases that the first certainty the practitioner acquires respecting the nature of the disease with which he has to deal, is from the effects of the remedies administered for its removal; whether these effects shall be such as to confirm him in the correctness of the opinion upon which his mode of practice has been founded, or to satisfy him of the error of his diagnosis. It must not be forgotten, however, that inferences of this kind must be subject to the numerous fallacies to which the judgments of medical men, respecting the influence of remedies over diseases, are exposed. Thus, it is well known that medical men long imagined that the most certain test of a syphilitic or non-syphilitic taint in particular cases was to be derived from the fact whether or not the malady disappeared when no mercury was employed; an opinion which recent experience has shown to be wholly without foundation. In modern times Italian physicians have established, as a general law in pathology, a principle, which they designate the law of tolerance of medicines, that would, if well established, render a knowledge of the juvantia and ludentia a very powerful assistance in forming our diagnosis, and particularly in judging of the intensity of a disease. The principle to which we allude is, that the human body, in becoming diseased, acquires the faculty of supporting medicines suited to its state, in doses exactly proportional to the intensity of the disease; and that it loses this faculty in proportion as the disease diminishes, and in the ratio of its diminution.
It has generally been understood, that when there existed a doubt as to the inflammatory or non-inflammatory character of a disease, a cautious trial of blood-letting might advantageously be made, with a view to throw light on the nature of the disease, and to determine the proper mode of treatment to be pursued. "The effects of remedies carefully considered," says Dr. Marshall Hall, "throw an important ray of light upon the nature and force of the disease, and upon the condition and energies of the system." (i. 1.) And in reference to this proposition the author observes, "One of the sources of diagnosis enumerated constitutes a department of knowledge which may be termed new: it is that of the effect of remedies, and especially of blood-letting, as a diagnostic of diseases, and as a criterion of the general powers of the
system. In cases in which it is doubtful whether the pain or other local affection be the effect of inflammation or of irritation, the question is immediately determined by placing the patient upright, and bleeding to incipient syncope: in inflammation much blood flows; in irritation, very little. The violence of the disease, the powers of the system, and the due measure of the remedy, are determined at the same time. There is, in my opinion," adds Dr. Marshall Hall, "no single fact in physic of equal importance and value in the diagnosis of acute diseases and the use of an important remedy." (P. 2, 3.) How far this application of the Italian doctrine of tolerance of medicines to the practice of blood-letting affords a safe rule of practice, we cannot here inquire; but we may observe, that common opinion assigns more influence in the production of syncope from venesection to individual constitution, than to the nature or intensity of the disease for which it is practised.
Lastly, when a case, respecting the exact nature of which any doubt has existed, proves fatal, it is of great importance that the practitioner should have an opportunity of confirming or correcting the judgment he may have formed, by the examination, after death, of the several organs and systems of the body; for though the information then acquired can be of no practical use in the individual case, and the seeking it may, with the ignorant, expose the medical man to Molière's sneer, "d'aviser et voir ce qu'il aurait fallu faire pour guérir un homme qui mourut hier," it may on a future occasion exempt him from doubt, or rescue him from error. It cannot be questioned that a much greater degree of precision than formerly prevailed in medical diagnosis has been introduced, and is in the course of being introduced, into this branch, since medical men have become duly aware of the importance of examining dead bodies for the purpose of determining the existence or non-existence, in particular diseases, of organic alterations of structure, and, when these exist, of ascertaining their nature and seat. But in endeavouring to connect the symptoms that manifest themselves during life, with the morbid alterations of structure found on examination after death, much attention is requisite, as has been already hinted, to enable us to discriminate between those structural changes that give rise to diseases, and those that only develop themselves during their progress, or the existence of which may be merely fortuitous. "Multum prodesse ad intelligendas morborum causas cadaverum sectionem," says Van Swieten in his Commentaries on Boerhaave's Lectures (sect. 1041), "nemo dubitat; interim tamen magnâ cautelâ hic opus est, ne pro morbi causa habeatur illud, quod potius morbi effectus est; multa enim in cadavere inveniuntur mutata per morbum ipsum, quæ non præ-exstiterant ante morbum." To assist us in this discrimination, it is very desirable to have an opportunity of making post-mortem examinations in every stage of the progress of a disease. But in some diseases in which there is no tendency to death, particularly in their early periods, it is only by availing ourselves of deaths accidentally occurring that we are able to ascertain whether the disease depends primarily on organic or structural lesions, and, if so, of what nature these may be.
It would perhaps be impossible to refer to a more happy illustration of the reciprocal light which the attentive examination of the symptoms that present themselves during life, and the careful inspection of the structural lesions met with after death, are calculated to throw upon one another, than is afforded by the connection traced by Dr. Bright between a particular affection of the kidney (now well known to medical men under the name of its first accurate describer), and a train of symptoms too often forcing themselves on the attention of the medical practitioner, but which had never before been recognised as depending on a specific pathological condition or proximate cause. It must, we conceive, be acknowledged upon all hands,
that the farther medical inquiries have been pushed, the smaller has the number of diseases become which are not known to be connected with, if not immediately dependent upon, perceptible alterations in the structure of particular portions of the body; or, in other words, that the diseases reputed dynamic have gradually diminished, while those reputed organic or structural have proportionally increased in number. It may be doubted, however, whether medical men, in their anxiety to trace the symptoms of diseases to organic causes, have not occasionally attributed to structural alterations a greater influence in the production of these phenomena than they actually exercise. For, even when structural alterations are found in the organs which, during life, had exhibited symptoms of a deranged condition, it does not necessarily follow that these symptoms and organic alterations were immediately and necessarily connected. In many cases, indeed, the symptoms seem to depend rather on some superadded dynamical derangement, than on the change of texture which has occurred.
In corroboration of this opinion may be mentioned the well-ascertained facts, first, that the same organic lesion which in one individual is accompanied with well-marked symptoms, in another individual may give rise to no indication of its existence, which, indeed, may become known only on examination after death; secondly, that the same combination of symptoms which post mortem examination would lead us to refer in one case to obvious organic alterations, may be found in another case totally unconnected with any perceptible change in the structure of any part of the body; and, thirdly, that in some cases of disease in which organic alterations are found after death, the symptoms have exhibited during life a periodical or intermittent character, which could not be the case if they depended simply on organic alterations of structure, seeing that these are not subject to variation. Thus, in a large proportion of epileptic subjects, organic alterations have been met with in the encephalon; but, in the first place, it sometimes happens that similar organic alterations are found after death in cases in which no symptoms of epilepsy occurred; in the second place, in some cases of epilepsy, no marks of organic disease can be detected; and, in the third place, though the organic alterations found in a number of cases of epilepsy may possibly account for such deviations from the healthy exercise of their functions as are manifested by some epileptics between their paroxysms, we must suppose that some other morbid condition of the encephalon, not permanent in its existence, but only occasional in its occurrence, is requisite for the production of the paroxysms themselves. "We know," says an intelligent author,1 "that morbid alterations in the substance of the brain sometimes produce periodic dis-
eases, and that certain additional causes of excitement operating upon an unsound brain, one or other of the functions of that organ is for a time impeded, till the new cause ceases to operate, when the individual immediately returns to his former state of apparent health."
In attempting to distinguish between those diseases which are referrible to an organic pathological condition, and those which are to be considered as dynamical, in the sense that has elsewhere been explained (in the article PATHOLOGY), it is necessary also to keep in mind that a deranged exercise of some, at least, of the functions of the economy, though not originating in any perceptible alteration of structure, may in its continuance give rise to some such alteration. The morbid appearances met with on the examination of dead bodies may, consequently, sometimes stand in the relation of effect to the derangement of function, and the consequent symptoms, of which medical men are disposed to regard them as the cause. "Les troubles des fonctions de la vie," said M. Prost, "et les altérations organiques, sont la double source des maladies, qui s'enchaînent, s'accroissent, et se reproduisent mutuellement."2
There is another source of fallacy in the attempts made by medical men to refer the symptoms that present themselves during life to such altered appearances as are found after death, in the different textures and organs of the body. We allude to certain changes that are liable to occur during the last periods of life, or even subsequently to death, and which those who are not duly warned of their occurrence, or not aware of the characters by which they may be distinguished, are liable to regard as products of disease. Much has been done, of late years, to facilitate the distinction between truly morbid, and, as they are termed, pseudo-morbid appearances, particularly between those turgescences of the extreme vessels which do, and those which do not, depend on inflammatory action. But, even from the difficulties that have presented themselves in establishing the grounds of distinction between these two sets of appearances, it may be inferred, that when these distinctions were not sufficiently understood or attended to, the symptoms that had manifested themselves during life must not unfrequently have been supposed to find their explanation in altered appearances of different textures and organs, which were not in reality products of morbid action.
From these observations, it is obvious that medical men require to be at all times equally on their guard against attributing to mere dynamical disturbance morbid phenomena which depend upon organic alteration of structure, and against attributing to structural alterations phenomena that arise simply from dynamical derangement. (L.)
1 Mackenzie on the Eye, p. 765.
2 Médecine Éclairée, p. 111. See reasons assigned by Dr Abercrombie (on Diseases of the Brain, 3d edit. p. 217) for believing that the affection which has been called Serous Apoplexy is to be considered as Simple Apoplexy (that is, apoplexy not depending on any perceptible deviation from healthy structure) terminating in effusion.