The terms pest, pestilence, and plague, were long employed in Great Britain, as were the corresponding terms in other languages, both in ancient and in modern times, to denote simply a disease attacking a great number of persons simultaneously and in succession, and destroying a large proportion of those whom it attacked; in short, a widely-diffused and malignant epidemic. At the present day these terms are restricted to signify a particular form of disease, of frequent occurrence in the countries bordering on the eastern extremity of the Mediterranean, the Levant and Archipelago, but occasionally appearing also in countries more or less remote from these regions.

The disease in question, the plague of the Levant, as it is often termed, exhibits, not in every individual case, but in a large proportion of those affected in the progress of its epidemic prevalence, two classes of symptoms, the constitutional and the local. Under the constitutional symptoms may be comprehended those indicative of fever of a malignant or typhoid character, with various concomitant phenomena that are in wont to attend fever of this character in different regions of the globe; the local consist chiefly of glandular swellings, or buboes as they are termed, and of malignant or gangrenous boils or carbuncles.

These two classes of symptoms stand variously related to one another in different individual cases; and even, there seems reason to believe, in different periods of the same epidemic. Dr Patrick Russell, in his Treatise of the Plague, in which he has given the results of his own extensive observation of this disease during its epidemic prevalence in Aleppo in the years 1760, 1761, and 1762, mentions one class of patients who seldom or never had buboes or carbuncles; and another class, in a few of whom, when the disease proved quickly fatal, these symptoms were likewise absent. "These two eruptions," he says, "are equally diagnostics of the true plague; their presence, separately or in conjunction, leaves the nature of the distemper unequivocal; but fatal has been the error of rashly, from their absence, pronouncing a distemper not to be the plague, which in the sequel has depopulated regions, and which early precaution might probably have prevented from spreading." Dr Louis Frank, also, mentions, that though the appearance of buboes is the most constant and characteristic symptom of the plague, yet he has seen many affected with this disease, in whom buboes were altogether wanting, or appeared only at the period of death. As cases of this kind are particularly liable to occur at the commencement of an epidemic, a considerable number of persons may, it is obvious, come to be affected, before the pestilential character of the disease is ascertained, or even suspected, particularly in regions in which the plague is of rare occurrence.

But as the constitutional symptoms of plague may occur without the local, so the local may occur with little fever or constitutional disturbance of any kind. Dr Russell, under his fifth class of cases, to which he refers those of slight infection, in which all the infected recovered, and which, he says, "was very numerous," mentions, that in these the access was often attended with so little apparent disorder, that the eruptions gave the first alarm; "the buboes were often the first symptom of infection;" and the fever, which came on afterwards, was frequently so slight as not to confine the sick to the house; others found themselves indisposed for two or three days, but were not sensible of any febrile heat whatever. In these cases, and in some others—in which the fever ran somewhat higher, but without the concurrence of alarming symptoms, "all the infected had buboes or carbuncles, and very often both eruptions concurred in the same subject." Persons not confined by indisposition were often, by the inguinal buboes, prevented from walking abroad.

In cases of plague in which both the constitutional and the local symptoms manifest themselves, there is considerable difference in the relative time of their appearance. "In a very large proportion of the sick," Dr Russell informs us, "the buboes made their appearance in the course of the first day; but in many instances they did not appear before the second or third day, or even later."

In the few remarks we purpose to offer relative to the plague, we shall consider some points of its natural history, as it presents itself: 1st, in the countries in which it is of frequent occurrence; and, 2nd, in those countries in which it rarely shows itself.

I. In the countries bordering on the Levant and Archipelago, the plague is liable to present itself either in single, or, as they are termed by medical men, sporadic cases; or in a great number of cases simultaneously or in succession, so as to constitute an epidemic.

It is stated, indeed, by Dr Patrick Russell, that "in the intervals between the plagues of Aleppo," that is to say, between the successive epidemic prevalences of this disease, "the city remains absolutely free; and the plague is never sporadic there, except in its beginning and decline; it never subsists for any length of time in a few scattered cases without consequence." But this statement is not conformable with the reports of others. M. Pugnet, who accompanied Bonaparte's expedition to Egypt, affirms, in his Mémoire sur les Épidémies du mauvais caractère du Lévant, that that country is seldom absolutely free from the plague during several successive years; and that in almost every month of every year there occur a number of cases, though these are not noted when they do not occasion its epidemic prevalence. Sir James MacGrigor, who had the medical charge of the army which was brought from India to Egypt in 1801, in like manner expresses his belief that "the contagion of plague is seldom or never out of Egypt."

Dr Murdoch Mackenzie, in his Letters concerning the Plague at Constantinople, published in the Philosophical Transactions, vol. xlvii., remarks, that during the twenty years he had lived at Constantinople and Smyrna, there had scarcely been a year, excepting three, in which the plague did not threaten more or less, with little or no perceptible difference in the character of the season to explain it. The late Sir Thomas Maitland, who had occasion, whilst governor-general of Malta and the Ionian Islands, to apply his vigorous mind to the investigation of the natural history of the plague, came to the conclusion, that, though subject to variations in respect of prevalence in the countries in question, this disease is never wholly extinct in any of them. "We find," says Sir Thomas, "that, whether it be in Egypt, at Smyrna, or Constantinople, an effort has been made to convince the world that the plague stops in these places at certain seasons, and commences at others. For my own part, I can only say, that he would be a bold man who would venture to assert that the plague ever is eradicated at any season of the year, in any one of the three places just mentioned; on the contrary, I hold nothing more certain, than that it constantly exists in them all, showing itself with greater violence at one time than at another, and hardly taken notice of till it arrives at such a height as to be seriously alarming to the whole community."

Various estimates have been given of the frequency of plague epidemics in the principal towns of Egypt, Syria, of its epidemic prevalence. Prosper Alpinus, who resided in Egypt between 1580 and 1584, refers to a belief of its recurring in that country every seventh year, but represents this belief as being incorrect. Dr Alexander Russell mentions it as the common opinion of the inhabitants of Aleppo, that they are visited with the plague about once in ten years; which opinion, he observes, seems in some measure to be founded on experience. Dr Mackenzie, writing from Constantinople in 1763, says, that "the plague is now more frequent in the Levant than it was when I first came into this country, about thirty years ago; for then they were almost strangers to it in Aleppo and Tripoli of Syria; and they had it, but seldom at Smyrna; whereas now they have it frequently at Aleppo, and summer and winter in Smyrna, which," he adds, "must be owing to the great communication by commerce all over the Levant; and more extended into the country villages than it used to be."

When the plague assumes an epidemic character in the countries in which it is common, the epidemic frequently once continues for several years; not, however, uninterruptedly, for in general it is observed, that for a part of the year, the disease in a great measure or altogether disappears, breaking out again after an interval of various duration. In the same way, in non-epidemic seasons, sporadic cases of plague are seldom or never met with during a particular portion of the year. It seems reasonable to conclude that this disappearance of plague, or great abatement in its prevalence, during a particular portion of the year, must be connected with some peculiar condition of the weather then prevailing, and consequently that the period must be liable to variations, not only in different countries, but also to some extent in the same country in different years.

Dr L. Frank mentions his having been assured that at Cairo the time of year in which the operation of the plague—which this poison is suspended uniformly commences with the summer occurs solstice (21st June), as stated by Prosper Alpinus with regard both to that city and to Egypt generally; but that at Alexandria, Rosetta, and Damietta, that is, in the towns along the coast, the plague terminates about the feast of St John (24th June), though not uniformly every year, as it sometimes continues till about the middle of July. In respect to the period of the plague's terminating at Cairo, Dr P. Russell mentions, that several accounts which, on making strict inquiry, he received from persons long resident in that city, Europeans as well as natives, all concurred in the fact of the plague's declining rapidly in June, but not ceasing entirely; and he particularly refers to information which he had received of the Europeans having remained, in 1759, shut up till the middle of July, "which was considered as very extraordinary." Dr Russell also remarks, that in most places in the Levant, a popular tradition is to be found of the extinction of the plague at a certain fixed period, which varies, however, at different places. At Aleppo, he adds, it is fixed nearly a month later than at Cairo. His brother, Dr A. Russell, states, that at Aleppo the plague comes to its height in June, decreases greatly in July, and certainly disappears in August. Mr Dawes, chaplain to the factory at Aleppo, says, that in all the plagues with which Aleppo had been visited in the eighteenth century up to that of 1761, the contagion is said to have regularly and constantly ceased in August and September. But that which prevailed in the year last mentioned proved the fallacy of general observations on this subject; for, from the end of March 1761, to the middle of September 1762 (that is, for a continued period of seventeen and a half months), scarcely a day passed without some deaths or fresh attacks from the distemper; and though its violence ceased in autumn, yet on an average he believes it was fatal to at least thirty persons in every week, from that time to the end of the winter. Dr P. Russell, in reference to the same epidemic, says,—“The natives all agreed in declaring the plague had never before been so formidable in the winter; and many went so far as to affirm that it was the first instance of the plague’s having been ever known at all at that season. But what happened in the year 1742 was entirely forgotten; and the cases in the present winter, however strongly marked, will probably, in the course of a few years more, be obliterated from the memory of the people of Aleppo, leaving them as tenacious as before of a traditionary opinion, that the city stands secure from the plague in the winter.” At Smyrna, according to Mr Hayes, the virulence of the disorder is almost invariably over by August. From the statement of Dr Mackenzie, it appears that the plague began at Constantinople in 1751 about the middle of May, and continued uninterruptedly more than sixteen months, that is, up to the latter end of September 1752. In 1753, it began the last day of May, and continued uninterruptedly till the middle of September 1754.

Admitting that, in general, though certainly not universally, plague disappears in Egypt soon after the 21st of June, in Syria about a month later, and probably at a still more advanced period of the year in Asia Minor and Turkey, is there any constancy in regard of its re-appearance? Sir J. McGrigor mentions that the month of November, or more usually of December, is the time of year in which the plague is wont to re-appear in Egypt, and that, according to the observation of the natives, when it breaks out before December, they have always a generally prevailing and very destructive disease. According to Pugnet, there are three periods in the prevalence of the plague in Egypt: its invasion, which occupies the months of December, January, and February; its acme, which occupies March, April, and May; and its extinction, which occurs suddenly during the second half of June. Frank says, that, according to the general accounts, the plague seldom occurs in Egypt in the months of September, October, November, December, and January, but usually appears in the months of February, March, and April; and he adds, conformably with Sir J. McGrigor’s statement, that “it is well ascertained, that when it begins in September or October, it is more terrible than if it appears later, because it then continues for a longer time, and is the cause of greater mortality. Perhaps, also, the pestilential miasm becomes more deadly.” At Aleppo, according to Dr A. Russell, the plague is constantly moderated during the winter, and grows more violent as the spring advances. Mr Hayes mentions the months of March and April as the period at which the plague usually begins at Smyrna. Timone states in regard to the plague at Constantinople, that it is pretty soundly lulled by the cold of winter, emitting, however, here and there sparks during that season as well as in spring; it increases in summer, and rages with the greatest violence in August. The spread of the infection is not stopped by the coldish north winds blowing at stated times of the summer; but if the south winds blow during that season, constantly and of sufficient warmth, they suppress the plague.

We shall presently have occasion to see the application of these facts relative to the periods at which the plague subsides and revives in Egypt, Syria, and Turkey, to the explanations that have been proposed of the causes or agencies by which this disease is produced.

Great difference of opinion has subsisted as to the nature of the agent which, by its operation on the animal economy, produces this form of disease; whether the plague is generated by a particular state of the atmosphere, itself the result of the reciprocal action of various concurrent agents, and which is sufficient to produce the disease in a large proportion of those who are exposed to its influence, as is the case in respect of ague or intermittent fever; or whether the disease is communicated from person to person through the medium of some impalpable effluvium from the body, as in the cases of measles and scarlet fever? Whether, in the language of medical men, the plague depends on terrestrial or atmospheric miasm, improperly named infection by some, or upon human contagion.

The laws of quarantine, so far as they refer to the plague, obviously proceed on the supposition that this disease is capable of being communicated by person to person; and also that the plague-poison is capable of being imbibed by substances that have come into contact with the bodies of those affected, or that have been exposed to the air which they breathe; of remaining attached to such substances for a considerable space of time, when excluded from free ventilation; of mixing with the atmosphere when exposed to it, and infecting those who breathe it; or of communicating the disease to persons who touch or handle the articles to which it is attached. The inconvenience with which the enforcement of the quarantine laws is necessarily attended, particularly to those engaged in commerce, has naturally rendered many anxious for their repeal or modification. The grounds upon which those who have represented them as unnecessary have rested their case, may be referred to the two following: 1st, That the plague always depends on miasm, and consequently, where the circumstances necessary for the production of plague-miasm concur, the disease will happen in spite of all quarantine regulations; and, 2d, that supposing the disease to be contagious, there are climates in which its contagion cannot be received and propagated, and consequently, as regards these, quarantine laws must be superfluous.

The evidence in favour of the contagious character of the plague in Egypt, Syria, Turkey, &c., and of its dissemination both by person and by fomites, as deduced from the places and individuals that escape, as well as from the places and individuals that become affected, is so ample and complete, as to leave room for doubt only in minds pre-occupied with theoretical dogmata, or considerations of personal advantage. Accordingly, the opinion adverse to the contagious character of plague in these countries, seems to be now very generally abandoned by those who can be regarded as impartial and competent judges of the fact. When a select committee was appointed by the House of Commons in 1819, to consider the validity of the doctrine of contagion in the plague, all the medical men examined, with the exception of two, were in favour of the received doctrine, that the plague is a disease communicable by contagion. One of these anti-contagionists in plague was Dr Charles Maclean, the other Dr Mitchell. Of the medical officers of the French and English armies in Egypt between 1799 and 1802, who have published an account of the diseases which presented themselves to their observation during that campaign, Assulini seems to have been the only one who came to the conclusion that the plague is not a truly contagious disease, and that it is produced solely by local causes.

By some, however, it has been supposed that both terrestrial miasm and human contagion are concerned in also spreading the plague, the disease being first generated by terrestrial miasm, but subsequently diffusing itself, by contagion, both in the districts in which the miasm is produced, and in countries to which it does not extend, and in which it can- not be supposed to be generated. Amongst those holding this doctrine, there has been a difference of opinion as to the number of districts in which the supposed plague-miasm may be produced. Some conceive that there is one particular portion of the globe only in which the circumstances essential for the development of plague-miasm occur in combination; an opinion readily adopted by the different nations and provinces among whom the disease frequently prevails, though they differ very much as to the parent soil, each being desirous to transfer that odium from itself to its neighbour. M. Fodéré, who, though he had never personally seen the plague, had bestowed much pains in studying its history, maintains that the plague is a production of the soil of Lower Egypt alone; that is to say, of the combination of the waters of the Nile, and of the materials brought down by that river, with the vegetable earth of the Delta, when, after the inundation, the heat causes these waters to be volatilized, and gives rise to the creation of an immense multitude of insects and reptiles. When the disease has once been produced in the human body by this miasm, he has no doubt as to its being capable of being communicated from person to person. He holds, therefore, that in Lower Egypt, the plague is both an endemic and a contagious disease; whilst, when it occurs in Upper Egypt, in Syria, and the other countries of Turkey, and in Europe, it is simply a contagious disease, being transported to them from Lower Egypt.

Others, again, are of opinion, that in Egypt, as elsewhere, the plague always requires a human effluvium for its production and communication; but that the propagation of this contagious effluvium is greatly influenced by, if not dependent upon, particular conditions of the atmosphere. This unknown condition of the atmosphere is supposed either to cause the effluvia of non-pestilential diseases to assume a pestilential character, or the plague-effluvium to be generated of a peculiarly virulent character, or to render the human body more susceptible of its action. The influence of the atmosphere in promoting and in checking plague seems sufficiently established by the circumstances already stated relative to the variations in its prevalence in the different seasons of the year; but in what manner or by what qualities the atmosphere exerts this influence, is a matter of the greatest uncertainty.

Some authors have been of opinion, that it is simply the temperature of the atmosphere which determines the prevalence of plague in the countries along the shores of the Mediterranean; that the atmosphere may be either too hot or too cold for its propagation. Thus Dr A. Russell mentions, that the season wherein the plague always ceases at Aleppo, is that in which the heats are the most excessive. "Extreme heat," he says, "seems to check the progress of the disease; for though, during the few first hot days, the mortality, as well as the number of those newly infected, increase, yet a few days' longer continuance of that weather greatly diminishes the number of the sick." Mr Dawes, in mentioning August and September as the months in which the plague usually, though not constantly, ceases at Aleppo, notices them as being the hottest months in the year. Conformably with the same view, the occurrence of the hot winds is conceived by some to be the agent which puts a stop to the prevalence of the plague in Egypt. From the statements of Timone, and of several other authors, as we have already seen, it appears that, at Constantinople, the cold of winter generally exercises a great influence in suppressing or diminishing the extension of this disease. Dr James Frank, who was upon the expedition with Sir Ralph Abercromby in the year 1800, and had the first establishment of the Plague Hospital at Aboukir, says, in his evidence before the committee of the House of Commons in 1819, "the great cold of Constantinople puts an end to it, and the great heat of Cairo puts an end to it." And to the same effect Mr Edward Hayes, a native of Smyrna, and who had resided there nearly forty-four years, on being asked by the committee, "When does the plague generally subside in your country?" replied, "When the great cold or the great heat destroys it."

M. Pugnet, again, affirms that the prevalence of the plague in Egypt is always proportional to the moisture of the atmosphere taken in connection with its heat, whether the moisture shall depend on a greater than usual inundation of the Nile, or on the fall of rain; and explains by these different sources of moisture the plague making its appearance in different districts of Egypt in different years. The circumstance of the heat bearing either a very great or a very small proportion to the moisture of the atmosphere, is, according to Pugnet, unfavourable to the extension of plague; but at the same time he holds, that besides moisture and heat, the germ of the disease, as he terms the contagious principle, is requisite for its development. In noticing that most of those who have travelled in Egypt say the plague is brought there from Greece, and those who have travelled in Greece pretend that that country only receives it from Egypt, M. Pugnet remarks,—"I think that the defenders of Egypt and those of Greece are equally in the right; the plague comes no less from Egypt than from Greece, or from Greece than from Egypt. It has established itself a double focus in these two opposite points; and when one of them seems to become extinguished, the other revives it."

Dr L. Frank, who, after sojourning with the French army Supposed in Egypt, subsequently resided for a year in Tunis, and travelled for six years over the continent of Greece, principally for the purpose of investigating everything connected with the plague, is adverse to the idea of the production of the pestilential poison being in any way connected with the overflowing of the Nile. The Nile begins to decrease in September, and in December all the waters disappear from the inundated surface. Consequently, he argues, if the putrefaction of stagnant waters could produce the plague, this disease should manifest itself chiefly in the months of October, November, and December, whilst, in fact, it very rarely occurs in these months. And as the increase of the Nile in the month of June is very small, it cannot be supposed to be the occasion of the extinction of the plague which occurs at that season. Besides, the plague occurs in some years when the increase of the river has been small, and does not occur in other years when the increase has been considerable. Frank has no doubt that the plague may be generated in Egypt; but in many instances he thinks it is imported into it from other countries, just as it is liable to be carried from it to other countries. He suggests, that when the plague manifests itself rapidly without any other epidemic having preceded it, it has probably been imported; but that when an epidemic, petechial, malignant, or nervous fever has previously occurred, it is very probable that these diseases have degenerated, and produced the contagious principle of the plague. Frank conceives, with Al-Depenpinus, that it is in the character of the winds that the prevalence of the plague in Egypt is to be looked for; the unhealthy season corresponding with the prevailing part of the year during which the winds and weather are variable, and the healthy season with the period during which the north wind blows steadily, that is, from June to September.

Those who, in admitting the contagious character of the Supposed plague, have argued in favour of the possibility of its poison being engendered independently of human effluvia, plague-poison being and simply from the reciprocal action of the atmosphere and the earth upon one another, seem to have been led to deduce this view by their believing that the plague-poison is wholly time to be extinguished during a certain portion of the year, and con- sequently, that for the reproduction of the disease there must be a reproduction, or *generatio de novo*, as medical men term it, of the poison.

When by the return of the period of the year which is unfavourable to its dissemination, the plague ceases, one of two things may happen. It may remain absent from the country or district for a succession of years, or it may recur with the period of the year which is compatible with its propagation. Now it does not appear to be necessary, in either of these cases, to admit the supposition of a fresh generation of pestilential poison from terrestrial miasmas. In the case of the shorter interval, the epidemic may have slumbered, but not died; in short, there may have occurred sporadic cases of the disease, in sufficient number to maintain the stock. When, again, a more considerable interval elapses between the cessation of the plague and its re-appearance at a particular place, a fresh importation may have taken place from regions in which it has been prevailing epidemically during its absence from the country under observation.

Besides being maintained by sporadic cases during the non-epidemic season of the year, the contagion of the plague may also be maintained in the form of *fomites*, that is, attached to substances that have been in contact with the bodies of patients, or exposed to the air which they breathe. Dr Russell mentions, that at Aleppo, in 1762, several instances occurred of the revival of plague in houses which had suffered the year before, attended with circumstances highly suspicious of the contagion having been preserved several months for want of cleansing. It has very generally been believed, also, that by fomites the contagion of plague may be carried to regions very remote from that in which these substances acquired it. When the articles to which the pestiferous poison has attached itself are freely exposed to ventilation, it does not seem to be retained for any considerable length of time; but when, on the contrary, they are excluded from open communication with the air, there is good ground for suspecting that the poison may remain attached to them for a long space of time. Indeed we are not acquainted with any natural limit to its continuance, besides that of the free exposure of the fomites to the air.

In considering the plague to be capable, at least during a certain portion of the year, of being diffused by contagion, it is not necessarily inferred that all persons who approach within a given distance of a person labouring under the disease must become affected with it. There seem to be a variety of circumstances that diminish the probability of infection, with some of which we are more or less acquainted, whilst of others we are entirely ignorant.

1st, It has been supposed that exposure during one period of the epidemic is attended with less risk of infection than exposure during another. 2d, That exposure to a mild case of plague is attended with less risk of infection than exposure to one of a very malignant character. 3d, That a person who is exposed to plague-contagion by degrees, runs less risk of infection than one who is suddenly brought within the sphere of its operation. 4th, That persons possessing equanimity of mind, of temperate habits, &c., run less risk than those who are in opposite circumstances.

Individual peculiarities in respect of the susceptibility or non-susceptibility of plague-contagion are very singular and unaccountable; but not more so than are observed in respect of other contagious diseases. A person whose exposure to the affected has been slight and of short continuance, may be seized with the disease; whilst another who has undergone a very great degree of exposure remains free. And a person who has remained free during close and long-continued exposure, may ultimately become affected, without any change of circumstances, extrinsic or intrinsic, which it is possible to detect.

Dr L. Frank conceives that the proportion of persons who pass their life in Egypt without experiencing an attack of plague, is greater than the proportion of persons who never experience an attack of small-pox, which he reckons as scarcely one in ten thousand.

It has been much disputed whether having once passed through plague renders a person unsusceptible of re-infection; and if it does not afford absolute security against more than one attack, in what proportion of cases a second or more frequent recurrence takes place. Some authors have denied the reality, if not the possibility, of a second attack of plague; others have related, as very singular events, single cases which had been noticed in particular epidemics; whilst others again represent such occurrences as by no means rare. Dr Mackenzie mentions his having been assured by the Greek Padre, who took care of the Greek hospital at Smyrna for fifty years, that he had had the plague twelve different times during that period; and it is very certain, adds Dr Mackenzie, that he died of it in 1736. The abbé who took care of the Frank Hospital at Pera, assured Dr M. that he had had the disease at Constantinople and at Smyrna four different times.

In various respects it is extremely desirable to know what length of time may elapse between a person's exposure to plague-poison, and the appearance of the disease. On the decision of this question, it is obvious, the duration of personal quarantine should be founded. Dr P. Russell mentions, that at Aleppo, he met with no instance of the disease appearing later than the ninth or tenth day after the day of shutting up, in those who adopted that precaution. Sir J. M'Grigor, in noticing that in different people, and under different circumstances, there is the greatest variety in respect of the time the matter of the pestilential contagion takes before it comes into action, mentions one case in which ten days seemed to be the shortest period that could possibly have intervened; and another in which a person continued well till the seventeenth day after being placed in quarantine.

II. The few remarks which we have room to offer relative to the plague, as occurring occasionally in other regions than those bordering on the Levant and Archipelago, than those than those bordering on the Levant and Archipelago, must bear reference chiefly to the question, whether, admitting the plague to be a contagious disease in the countries we have hitherto alluded to, there is any reason to apprehend the possibility of its being introduced into the British isles; or whether the quarantine laws, as regards the plague, might be safely abolished. To justify such a measure, it would, it appears to us, be necessary to establish the correctness of one or other of the following propositions:—1st, That it is impossible, in the nature of things, that the plague should exist in the British isles; and that, in point of fact, it never existed in them: 2d, That if it ever existed in these islands, it was indigenous, not imported, and consequently could not have been prevented by quarantine laws: or, 3d, That if it ever was imported into these islands, it was under circumstances which cannot recur.

1st, Our opinion, as to whether a particular disease can occur in any country, may rest upon two grounds; the first, our belief as to the conditions on which its prevalence in the countries it is known to infest may depend; and the second, our knowledge as to whether it has ever prevailed in the country in former times. These two considerations may reflect mutual light on each other. If we are very certain as to the conditions requisite for the existence of the particular disease, and are told that it has occurred in a country which we know not to fulfil these, we will disbelieve the correctness of the statement. And, conversely, if we are perfectly satisfied that the disease has prevailed in a country which does not fulfil the conditions we are disposed to consider requisite for its exist- ence, our opinion as to these conditions must be modified.

In respect of the plague, it is plain, from the discrepancies which we have seen to prevail in the explanations given of the causes by which it is produced and propagated in Egypt, &c. that the reality of its existence is exposed to much less dubiety than the explanation of the conditions on which that existence depends.

The fact already mentioned, of the very wide significance that used to be attached to the term plague or pest, renders it necessary, indeed, that in judging whether a particular epidemic was really plague or not, we should not trust to the mere name which it received, but inquire into the symptoms which it actually exhibited. But, with symptoms so very characteristic as those that attend true plague, or rather, as we have already said, a large proportion of the cases that occur in the course of a plague-epidemic, a very slight description of a pestilence must suffice for determining as to its identity with genuine plague. Accordingly, we have experienced considerable surprise in looking over the evidence taken by the committee of the House of Commons in 1819, at the number of witnesses who either positively denied that the so-called plague in London of 1665 (to omit previous epidemics to which that title was applied) was really that disease, or expressed much doubt on the subject. If the general statement of Sydenham to that effect left any room for doubt on this head, the minute description of Dr Hodges, and particularly the portion of it that relates to the more peculiar symptoms, including buboes, carbuncles, &c., is more than sufficient, we should have thought, to remove all doubt from the minds of the most sceptical.

2d. As to the plague of 1665 having been indigenous, and not imported, we have a very explicit statement of Dr Hodges as to its having been brought from Turkey to Holland, and from Holland to England. Attempts have indeed been made to point out discrepancies in his explanation of its first appearance and propagation in England; but to us the objections appear inconclusive, and the deficiencies in the chain of proofs such as might occur in tracing the diffusion of a disease universally recognised as contagious. The non-recurrence of the plague in this country since that period is certainly not more easy to explain, on the supposition of the epidemic in question having been indigenous, than on that of its having been imported.

3d. The circumstances favourable to the reception and dissemination of plague-contagion, which may be supposed to have existed in 1665, but to be now extinct and incapable of recurring, may be of different kinds. The beneficial change may be in the character of the climate, in the condition of the soil, or in the habits of the people. But if our immunity has depended on a change in the climate, who can be responsible for the continuance of this change? What the climate has been, it may, for any thing we know, become again. And as to any immunity that could be supposed to result from a change in the habits of society, and particularly from the superior attention paid to cleanliness and ventilation in our cities, from the introduction of public sewers, &c., to which much importance has been attached, we must confess our apprehensions, that any seeds of disease which depend for their development upon filth, will not perish for want of a hot-bed in many districts of the larger cities of the three kingdoms.

A recent occurrence in Egypt forcibly inculcates the necessity of great caution in admitting, that in a country in which plague is known to have occurred, any changes have been effected, either in the soil or in the people, incompatible with its recurrence. Mr Edward W. Lane, in his Account of the Manners and Customs of the Modern Egyptians, written in Egypt during the years 1833, 1834, and 1835, says, "The climate of Upper Egypt is more healthy, though hotter, than that of Lower Egypt. The plague seldom ascends far above Cairo, the metropolis. It is most common in the marshy parts of the country near the Mediterranean. During the last ten years, the country having been better drained, and quarantine regulations adopted to prevent or guard against the introduction of this disease from other countries, very few plague cases have occurred, excepting in the parts above mentioned; and in those parts the pestilence has not been severe." But in a note Mr Lane adds, "This remark was written before the terrible plague of the present year (1835), which was certainly introduced from Turkey, and extended throughout the whole of Egypt, though its ravages were not great in the southern parts. It has destroyed not less than eighty thousand persons in Cairo, that is, one third of the population; and far more, I believe, than two hundred thousand in all Egypt."

If, from any of the circumstances alluded to, the British isles can be supposed to be free from the risk of the importation of plague-contagion, or of its diffusion in the event of importation, it is to be presumed that it does not enjoy this as an exclusive privilege, but must share it with other countries that are similarly circumstanced. It becomes necessary, therefore, to inquire in what countries, besides those immediately bordering on the Levant and Archipelago, we have occasion to believe that the plague has existed, or is capable of existing.

In the first place, of its liability to occur in the islands, and along the coasts of the more western portions of the Mediterranean, we presume no doubt can be entertained. In two of the Greek islands now under British dominion, viz., Corfu and Cephalonia, the plague occurred in 1816, in a form which left no room for doubt as to its real nature. In Italy, Malta, and the adjoining small island of Gozo, we have equally unquestionable examples of the occurrence of plague in recent times; witness that which occurred at Noja in the kingdom of Naples in 1816, and of which accounts have been published by Morea, Onofrio, and Schönb erg; and that which occurred in Malta and Gozo in 1818, of which accounts have been given by Calvert, Faulkner, and Tully. Previously to 1818, Malta appears not to have been infected with the plague for upwards of a hundred and thirty years, that is, since 1675; a circumstance not undeserving the consideration of those who are disposed to consider non-occurrence as implying impossibility of occurrence.

In Sicily, we are not aware of the plague having appeared in an epidemical form since the year 1743, when it raged at Messina.

Along the African coast we have accounts of the occurrence of the plague at Tunis in 1818, 1819, and 1820, by Passeri; and of its occurrence so far to the west as Tangier in 1818 and 1819, an account has been published by Graber di Hemso.

Of the plague-epidemics that have occurred on the northern shores of the western portion of the Mediterranean, that of which we possess the most circumstantial account is the epidemic of Marseilles in 1720. The descriptions of that epidemic given in the works of Chicoyneau, and of Bertrand and Michel, leave, we conceive, not the smallest room for doubt as to the disease having been genuine or Levant plague.

Of the extension of the plague from Turkey into more northern latitudes, numerous examples might be adduced. Between the years 1702 and 1711, it advanced by a gradual but steady course through the different provinces of Poland and Prussia to Danzig, and from thence extended itself to Copenhagen. (See the accounts of this epidemic by Gottwald, Chamberlayne.) Again, in the year 1769 and 1770, when the Russians and Turks were engaged in warfare, the plague passed from the Turkish confines through some of the Polish provinces, and thence into the Russian territories, and ultimately reached the city of Moscow. (De Mertens, Orricus, Samoilowitz.)

It has been generally considered as a well-established fact in regard to the plague, that it had not been seen beyond a certain degree of eastern longitude, Mecca being the limit that has usually been assigned to its extension in that direction. This fact has been supposed to confirm and to be explained by the notion of its contagious poison being rendered innocuous by a certain degree of atmospheric temperature. From recent communications from India, however, there seems too much reason to apprehend that the plague has at length made its appearance on the confines of the north-western district of Hindustan. The only accounts of the epidemic which has excited these apprehensions that we have yet had an opportunity of perusing, are contained in the first three numbers of the Quarterly Journal of the Calcutta Medical and Physical Society, published between the 1st January and the 21st July 1837. We are unable to lay extracts before our readers, but we may refer to the communications of Mr Maclean, Dr Irvine, and Dr Keir, therein contained, as leaving little room to doubt that the epidemic in question was true plague, though not in its most aggravated form.