or SANHEDRIN (synedrion, a council or assembly of persons sitting together), was the name by which the Jews called the great council of the nation, assembled in an apartment of the temple of Jerusalem to determine the most important affairs of their church and state. This council consisted of seventy senators. The room they met in was a rotunda, half of which was built without the temple, and half within; that is, one semicircle was within the compass of the temple, the other semicircle was built without, for the senators to sit in, it being unlawful for any one to sit down in the temple. The Nasi, or prince of the sanhedrin, sat upon a throne at the end of the hall, having his deputy at his right hand, and his deputy at his left. The other senators were ranged in order on each side.

The rabbins pretend, that the sanhedrin has always subsisted in their nation from the time of Moses down to the destruction of the temple by the Romans. They date the establishment of it from what happened in the wilderness, some time after the people departed from Sinai, in the year of the world 2514. Moses, being discouraged by the continual murmurings of the Israelites, addressed himself to God, and desired to be relieved at least from some part of the burden of the government. Then the Lord said to him, "Gather unto me seventy men of the elders of Israel, whom thou knowest to be the elders of the people, and officers over them; and bring them unto the tabernacle of the congregation, that they may stand there with thee: And I will come down and talk with thee there; and I will take of the spirit which is upon thee, and will put it upon them; and they shall bear the burden of the people with thee, that thou bear it not thyself alone." The Lord, therefore, poured out his spirit upon these men, who began at that time to prophesy, and have not ceased ever since. The sanhedrin was composed of seventy councillors, or rather seventy-two, being six out of each tribe; and Moses, as president, made up the number to seventy-three. To prove the uninterrupted succession of the judges of the sanhedrin, there is nothing unattempted by the partisans of this opinion. They find a proof where others cannot so much as perceive any appearance or shadow of it. Grotius may be consulted in many places of his commentaries, and in his first book De jure belli et pacis (c. iii. art. 20), and Selden De Synedris veterum Hebræorum; also Calmet's Dissertation concerning the Polity of the ancient Hebrews, printed before his Commentary upon the Book of Numbers.

As to the personal qualifications of the judges of this bench, their birth was to be untainted. They were often taken from the race of the priests or Levites, or out of the number of the inferior judges, or from the lesser sanhedrin, which consisted only of twenty-three judges. They were to be skilful in the law, as well traditional as written. They were obliged to study magic, divination, fortune-telling, physic, astrology, arithmetic, and languages. The Jews say they were to know seventy tongues; that is, they were to know all the tongues, for the Hebrews acknowledged but seventy in all, and perhaps this is too Sanhedrim, great a number. Eunuchs were excluded from the sanhedrin because of their cruelty, usurers, decrepid persons, players at games of chance, such as had any bodily deformities, those that had brought up pigeons to decoy others to their pigeon-houses, and those that made a gain of their fruits in the sabbatical year. Some also exclude the high-priest and the king, because of their power; but others will have it that the kings always presided in the sanhedrin whilst there were any kings in Israel. Lastly, it was required that the members of the sanhedrin should be of a mature age, of a handsome person, and of considerable fortune. We speak now according to the notions of the rabbins, without pretending to warrant their opinions.

The authority of the great sanhedrin was very extensive. This council decided such causes as were brought before it by way of appeal from the inferior courts. The king, the high-priest, and the prophets, were under its jurisdiction. If the king offended against the law, for example, if he married above eighteen wives, if he kept too many horses, if he hoarded up too much gold and silver, the sanhedrin had him stripped and whipped in their presence. But whipping, they say, among the Hebrews was not at all ignominious; and the king bore this correction by way of penance, and himself made choice of the person that was to exercise this discipline over him. The general affairs of the nation were also brought before the sanhedrin. The right of judging in capital cases belonged to this court, and the sentence could not be pronounced in any other place, but in the hall called Laschat-haggazith, or the hall paved with stones. Hence it came to pass, that the Jews were forced to quit this hall when the power of life and death was taken out of their hands, forty years before the destruction of their temple, and three years before the death of Jesus Christ. In the time of Moses this council was held at the door of the tabernacle of the testimony. As soon as the people were in possession of the land of promise, the sanhedrin followed the tabernacle. It was kept successively at Gilgal, at Shiloh, at Kirjath-jearim, at Nob, at Gibeon in the house of Obed-edom; and, lastly, it was settled at Jerusalem until the Babylonish captivity. During the captivity it was kept up at Babylon. After the return from Babylon, it continued at Jerusalem until the time of the Sicarii or Assassins. Then finding that these profligate wretches, whose number increased every day, sometimes escaped punishment by favour of the president or judges, it was removed to Hanoth, which were certain abodes situated, as the rabbins tell us, upon the mountain of the temple. From thence they came down into the city of Jerusalem, withdrawing themselves by degrees from the temple. Afterwards they removed to Jamia, thence to Jericho, to Uzzah, to Sepharvaim, to Bethsanim, to Sephoris, last of all to Tiberias, where they continued till the time of their utter extinction. And this is the account the Jews themselves give us of the sanhedrin.

Father Petav fixes the beginning of the sanhedrin not till Gabinius was governor of Judaea, who, according to Josephus, erected tribunals in the five principal cities of Judaea; at Jerusalem, at Gadara, at Amathus, at Jericho, and at Sephora or Sephoris, a city of Galilee. Grotius places the origin of the sanhedrin under Moses, as the rabbins do; but he makes it terminate at the beginning of Herod's reign. Basnage at first thought that the sanhedrin began under Gabinius; but afterwards he places it under Judas Maccabeus, or under his brother Jonathan. We see, indeed, under Jonathan Maccabeus, in the year 3860, that sanhedrin, the senate, along with the high priest, sent an embassy to the Romans. The rabbins say, that Alexander Janneaus, king of the Jews, of the race of the Asmonaeans, appeared before the sanhedrin, and claimed a right of sitting there, whether the senators would, or not. Josephus informs us, that when Herod was yet governor of Galilee, he was summoned before the senate, where he appeared. It must be therefore acknowledged that the sanhedrin was in being before the reign of Herod. It was probably in being afterwards, as we find from the Gospel, and from the Acts. Jesus Christ, in St Matthew (v. 22), distinguishes two tribunals. "Whosoever is angry with his brother without a cause shall be in danger of the judgment;" this, they say, is the tribunal of the twenty-three judges. "And whosoever shall say to his brother, Raca, shall be in danger of the council;" that is, of the great sanhedrin, which had the right of life and death, at least generally, and before this right was taken away by the Romans. Some think that the jurisdiction of the council of twenty-three extended to life and death also; but it is certain that the sanhedrin was superior to this council.

The Talmudical writers tell us, that besides the sanhedrin, properly so called, there was in every town containing not fewer than one hundred and twenty inhabitants, a smaller sanhedrin, consisting of twenty-three members, before which lesser causes were tried, and from the decisions of which an appeal lay to the supreme council. Two such smaller councils are said to have existed at Jerusalem. It is to this class of tribunals that our Lord is supposed to allude in the passage just quoted in Matthew v. 22. Where the number of inhabitants was under one hundred and twenty, a council of three adjudicated in all civil questions. What brings insuperable doubt upon this tradition is, that Josephus, who must from his position have been intimately acquainted with all the judicial institutions of his nation, not only does not mention these smaller councils, but says that the court next below the sanhedrin was composed of seven members. Attempts have been made to reconcile the two accounts, but without success; and it seems now very generally agreed that the account of Josephus is to be preferred to that of the Mishna, and that consequently it is to the tribunal of the seven judges that our Lord applies the term spirits in the passage referred to.

The origin of the sanhedrin is involved in uncertainty; for the council of the seventy elders established by Moses was not what the Hebrews understand by the name of sanhedrin. Besides, we cannot perceive that this establishment subsisted either under Joshua, the judges, or the kings. We find nothing of it after the captivity till the time of Jonathan Maccabeus. The tribunals erected by Gabinius were very different from the sanhedrin, which was the supreme court of judicature, and fixed at Jerusalem, whereas Gabinius established five at five different cities. Lastly, it is certain that this tribunal of the judges was in being in the time of Jesus Christ. A Jewish sanhedrin is said to have been summoned by Napoleon at Paris, on July 23, 1806, and it assembled on the 20th January 1807. Compare Otho, Lexicon Rabbinico-Philolog., in voce; Selden, De Synedris Veterum Barbariorum, ii. 95, sq.; Reland, Antig. ii. 7; Jahn, Archæologie, ii. 2, § 186; Pareau, Antiq. Heb. iii. 1, 4; Lightfoot, Works, plur. locis; Hartmann, Enge Verbindung des Alten Test. mit dem Neuen, s. 166, &c.; and Milman's History of Latin Christianity, i. Sanitary Science is that department of human knowledge which contemplates those laws of the human body, and of the agents by which it is surrounded, which tend to preserve life and ward off disease and death. The practical application of these laws results in the art of preserving health, which is called hygiene. Hygiene is sometimes defined as the art of preventing disease, in contradistinction to medicine, which is the art of curing disease. The general subject of hygiene has been treated variously by different writers. It is sometimes divided into public and private hygiene, and this is a common division amongst French writers on the subject. Public hygiene comprises the consideration of the healthy conditions and arrangements of all places in which human beings are collected together, as camps, barracks, ships, hospitals, prisons, workhouses, churches, manufactories, schoolhouses, &c. Private hygiene embraces the laws which regulate the health, life, and age of the individual.

We have divided the subject of sanitary science in this article into general hygiene and special hygiene. These divisions correspond in some measure to the above; general hygiene embracing the laws which regulate the health of the human body and determine disease, whilst special hygiene embraces the application of these laws to the sanitary wants of a community and the hygienic demands of industry.

It was an early experience of mankind that certain external agencies produce disease and death, and amongst the earliest nations of antiquity certain practices were inculcated for the prevention of disease, and securing health. In the books of Moses we have a surprising instance of the care which was taken to prevent disease by the inculcation of hygienic precepts, and the adoption of sanitary laws. Although these laws and precepts were part and parcel of the great religious system under which the Jews lived, and were superintended and enforced by the priests of that religion, there can be no doubt that one great end which they secured was the health of the people. Burdensome and unnecessary as some parts of the sanitary code of Moses might be regarded in countries like our own, they nevertheless, as a whole, comprise great principles of action, which it is somewhat astonishing should have been so entirely overlooked by the modern nations of Europe, who have for centuries regarded the mission and laws of Moses as divine.

In the distinction between clean and unclean beasts and birds we see those selected for food whose flesh was less likely to corrupt and putrefy, and thus to engender disease. In the forbidding the eating of blood, the most putrescible part of the animal was got rid of from the ordinary diet of the people. The regulations with regard to those who had leprosy and other cutaneous diseases were such as would prevent the spread of many of the forms of contagious disease with which we are acquainted at the present day. These precautions extended to the clothes and houses of those infected, and involve an amount of attention to the spread of infectious diseases that, if adopted with the modifications necessary for climate, and in accordance with modern science, would go far to suppress a large class of our zymotic diseases. Even the distinctive religious ordinance of circumcision seems to have had reference to sanitary requirements. In the practice inculcated of removing human excretions on to the soil, and using them as manure, we witness a procedure, and even obedience to a natural law, the neglect of which is now visiting with disease every city of Europe. The practice of burying the dead away from all human habitations, of embalming the body immediately after death, and even of burning, were all adopted by the Jews, and is indicative of the sanitary law under which those remarkable people lived.

Many of these practices, however, are not exclusively Jewish, and many of the oriental nations have carried into effect similar methods of securing the health of their teeming populations. We do not, however, find any sanitary code equally explicit with that of Moses amongst the nations of antiquity, unless we except the laws of Lycurgus, under which the Spartans lived, but which were peculiar, and especially adapted to the development of the military spirit amongst this nation of warriors.

The culture of the Greeks early led to the establishment of medicine as an art in the hands of the Asclepiade, who gave general directions for the prevention of disease to all who resorted to their temples of health for their advice. Amongst this class of men arose the great Hippocrates, whose works must be regarded as the first attempt to reduce to law the facts on which the art of preventing disease is founded. His great treatise on *Air, Waters, and Places* embraces a consideration of many of the questions which relate to public health, and may be read with advantage even by those who are acquainted with the facts and laws which modern science has made known. Amongst the institutions of the Greeks which seem to have had the health and strength of the community in view, we may specially refer to their gymnastic exercises, which were practised in schools especially devoted to the purpose.

Amongst Roman writers who referred to the subject of public health, we may especially refer to Celsius, whose excellent treatise on medicine contains a large number of hygienic precepts, and a philosophical perception of the importance of the subject. In the conduct of their great armies, the Romans on some points paid great attention to the rules of public health. The sites of their camps have always been regarded as examples of the care that was taken to secure localities free from the influence of injurious exhalations from the soil. They were also particular about the supply of water to their soldiers, and inculcated the practice of bathing.

The remains of Roman architecture also show that the supply of pure water to towns was regarded as essential to the welfare of their inhabitants. The practice of bathing amongst them, which undoubtedly originated in the conviction of its value in relation to public health, became converted, in the later periods of the empire, into a luxurious indulgence, to which has been traced in some measure the effeminacy which characterised the race during its decadence.

Amongst modern European nations, the subject of public health, as a branch of state action, seems to have attracted but little attention. When pestilences swept over the face of the earth, efforts were occasionally made to prevent their recurrence. The recognition and general spread of syphilitic disease in the sixteenth and seventeenth centuries led, in many countries of Europe, to legal measures for its suppression and control. Most countries in Europe adopted various quarantine regulations for the prevention of the introduction of this and other diseases. But it is said, with regard to the greater proportion of this kind of legislation, that the lack of intelligence it displayed was frequently so great as to lead to the doubt whether it did not do more harm than good.

In the conduct of the ships, camps, prisons, and hospitals in Europe, during the last century, many great and salutary improvements have been made, depending on the application of the laws of sanitary science. Previous to the time of the great circumnavigator Cook, the ships of Europe were floating lazarettoes. The shortest voyage involved a loss of life which, at the present moment, would be regarded as frightful in the longest voyages. Captain Cook claims not so much the admiration of mankind for his brilliant geographical discoveries, as their gratitude for first applying the knowledge of the laws of life to its preservation on board his ships. He first demonstrated that a ship's crew might be taken round the world without the loss of a single sailor. That curse of our navies, the scurvy, found its remedy, at the latter end of the last century, in the application of a knowledge of the dietetical necessity of fresh vegetables for its prevention. The diseases of our armies attracted the attention of medical writers to their prevention during the last century; whilst the exposure of the horrors of prisons by John Howard led to the general introduction of sanitary arrangements in their structure and discipline.

Moreover, we cannot deny to the municipalities of many of the cities of Europe an anxiety to secure, in many of their public arrangements, the health of the communities in which they lived. Many instances might be given of great works executed for the supply of water, the erection of markets, the construction of sewers, &c., with the public health in view. We owe it, however, more particularly to France that the health of the people should become a part of the care of the government. It is indeed wonderful that a subject so truly within the sphere of civil government should have been neglected so long, and that at the present no government of Europe should be able to present a consistent code of legislation on this important subject. At the latter end of the last century, the Royal Society of Medicine of Paris appointed a Committee of Health, to which was referred certain subjects connected with injurious emanations from manufactories, the condition of hospitals, prisons, and other sanitary measures. In 1802 the government of France constituted a Council of Health, for the purpose of superintending sanitary operations in Paris. This council has had its numbers increased and its powers extended, and at the present day consists of eighteen members. Its function is to inquire into all matters concerning public health. It examines into the sanitary condition of markets, cemeteries, slaughter-houses, sewers, dissecting-rooms, water-closets, pumps, wells and fountains, public baths, and prisons. It prepares tables of the statistics of mortality, of the sanitary condition of workshops, &c.; and suggests remedies for the prevention of inundations, and the utilizing and deodorizing injurious industrial products. It also undertakes the suppression of medical impositions of all kinds, and the analysis of foods and drinks suspected of adulteration or injurious properties. This body has published several volumes of valuable reports, which have been edited by MM. Parent Du Chatelet and Marc. The cities of Lyons, Marseilles, Lille, Rouen, Bordeaux, and Nantes followed the example of Paris, and had their councils of public health. In 1851 a law was introduced by which the whole of France was placed under the control of the central Council of Health, with departmental coun-

This plan has not hitherto produced the results hoped for, arising apparently from the too complicated nature of the machinery.

We now turn to England, where both the government and municipal bodies have been remarkably slow to recognize the importance of public measures for securing public health. There are two causes for this: first, an ignorance of the real causes of disease, and the means by which they may be prevented; and second, a religiousness of feeling which ascribes disease and death to the hand of Providence, and which leads to the impression, that human efforts are unavailing against these decreed visitations of the hand of God. It was not until the year 1831, when the cholera visited this country, that the public mind became awakened to the fact, that much of its destructive effect was the result of circumstances which could have been prevented by human foresight; and that such pestilences could only be avoided in future by greater attention to the conditions by which the life of the community is regulated. It is to the writings and labours more especially of Dr Southwood Smith that we are indebted to the sanitary legislation which commenced in this country after the first alarming outbreak of cholera in 1831. It was not, however, till the history of this disease pointed to the probability of its recurring again in this country that legislation commenced. In the year 1845 the "Nuisances Removal Act" was passed. This was, however, only a temporary measure, and intended to meet the exigencies of an immediate outbreak of cholera. This disease did not reach England till 1848, and then the Nuisances Removal Act became permanent. This act, although very defective, acknowledged the right of the magistrate to interfere in all cases where the circumstances of property or individuals, either alone or combined, led to the development of conditions which could produce disease. It awakened the public mind to the fact, that there existed in all our large towns preventable causes of disease; and much sanitary activity was the result.

Between the temporary and permanent passing of the Nuisances Removal Act, an act of great importance, in a sanitary point of view, was passed, and this was the Baths and Wash-houses Act. By this act vestries and local boards were empowered to erect baths and wash-houses, and to obtain funds for this purpose from public rates and funds. The poor were by this means supplied with one of the greatest necessities of our large towns,—water for washing purposes at a rate which enabled them to use it as extensively as their circumstances required. Upwards of twenty institutions of this kind have been established in London. The following table, drawn up for the use of the vestry of St James's, Westminster, will give an idea of the extent to which these institutions have been employed, and the sums received for their use:

| Number of Baths taken | Number of Women who have availed themselves of the Wash-houses | Name and Title of the Establishment | Receipts from Bathers | Receipts from Washers | Gross Receipts | |-----------------------|---------------------------------------------------------------|-----------------------------------|----------------------|----------------------|--------------| | 184,700 | 58,042 | St George and St Giles, Bloomsbury | £2,423 2 11 | £1,132 7 9 | £3,555 10 8 | | 136,381 | 24,945 | St Mary-le-bone | £883 4 8 | £631 12 1½ | £1,514 16 ¾ | | 124,693 | 38,680 | Goulston Square, Whitechapel | £177 0 0 | £771 0 0 | £948 0 0 | | 100,133 | 40,900 | St James, Westminster | £160 1 10½ | £899 6 2½ | £2,049 8 1 | | 90,471 | 24,577 | St Martin-in-the-Fields | £507 8 8 | £434 17 1 | £942 5 9 | | 89,524 | 27,063 | Bermondsey | £332 6 | £707 3 11½ | £1,039 7 3½ | | 80,223 | 48,752 | St Margaret and St John, Westminster | £986 9 | £868 11 11 | £1,854 20 2 | | 82,882 | 27,424 | St George, Hanover Square, Belgrave Place | £1,069 13 0 | £738 7 10 | £1,808 0 10 | | 81,943 | 22,503 | Do., Davies Street, Oxford Street | £1,057 6 1 | £627 9 4 | £1,724 15 5 | | 42,201 | 9,449 | All Saints, Poplar | £504 11 4 | £333 6 8 | £837 18 0 |

Total: 1,001,041 baths taken, 321,474 women who have availed themselves of the wash-houses. We may notice that the general conviction of the necessity of sanitary measures increased, and led to the introduction of powers for making provision for public health into acts which otherwise might have passed without these provisions. Among the Consolidation Acts of 1847 was the Towns Improvement Clauses Act, many of the provisions of which have since been embodied in other acts, and which contain a variety of clauses relating to the sanitary question. The great act, however, which forms the most distinguishing feature of the sanitary legislation of England, was the Public Health Act, which was passed in 1848. By this act a General Board of Health was constituted, at the head of which was a president appointed by the government. Under this act power was given to local authorities to construct public works of various kinds, but more especially for improving the drainage and water supply. Since the passing of this act, 236 towns have placed themselves under its provisions. These towns contain populations varying from 500 to 200,000. These are exclusive of places which have put in force various sanitary regulations under powers given them by local acts. The expenditure upon the works thus executed has been calculated to be not less than £3,500,000. Although this statement shows that a vast amount of sanitary activity has been called forth by the public health, it nevertheless gives but an imperfect idea of the indirect benefits which have resulted by the fixing public attention on the importance of the prevention of disease and death. The diminution of the mortality consequent upon the introduction of sanitary improvements in some of the towns of England will be seen from the following table:

| Names of Towns | Death Rate in 1890 | Number of Lives Saved per 1000 per annum | |---------------|-------------------|----------------------------------------| | Alnwick | 35-2 | 6-9 | | Barnard Castle| 33-3 | 7-4 | | Berwick | 28-5 | 7-3 | | Bangor | 35-1 | 4-2 | | Durham | 26-0 | 3-3 | | Ely | 25-6 | 6-3 | | Salisbury | 32-2 | 5-2 | | St Thomas | 26-9 | 3-9 |

It must not, however, be supposed that anything like a perfect system of public sanitary exertion exists even in the improved towns; and a large number of small towns and villages exist where the prevalence of fever and the high mortality indicates that little or nothing has been done for the improvement of the public health.

After ten years of successful operation, the Public Health Act was repealed in 1858, and the General Board of Health abolished. This arose partly from the nature of its operations being misunderstood, and partly from the activity of the board offending those who wished things to remain as they were, or wished to act for themselves. The Board of Health was really a board of works; and as they repudiated interfering actively in matters relating exclusively to hygienic arrangements, the name misled. The powers, however, granted under this act are still continued by the operation of the Local Government Act, and are still to be exercised by local bodies, and no cessation of the benefits of previous legislation is contemplated.

It was, however, considered necessary to give to some central body power to act in cases where disease reached a certain amount of fatality, or where fevers or other contagious diseases broke out with great violence; and a new "Public Health Act" was passed in 1858, which placed this power in the hands of the Privy Council. To this office is now given the power possessed by the General Board of Health under the act of 1848 and subsequent acts. This act, which was originally passed for one year, was made permanent in 1859.

Besides this great sanitary act, other measures have passed through the legislature which demand notice here. The Common Lodging-Houses Acts were passed in 1851 and 1853. Under the Public Health Act powers were given to local boards of health to register houses which were let out as common lodgings, and to inspect them, and regulate the number of their inhabitants. These powers soon brought to light the existence of a state of filthiness, indecency, and iniquity that led at once to the passing of the strongest possible measures for suppressing such sources of disease and moral degradation. Of the two measures referred to, one relates to the regulation of common lodging-houses, and the other is a permissive act, to enable public authorities to erect common lodging-houses. Under the first act, the commissioners of police in towns, and the justices of the peace in the country, have the power of regulating these places. The good that has been effected under this act has been very considerable in London and many large towns, although it is to be feared that not sufficient attention has yet been given to the overcrowding of private lodging-houses as the result of the supervision of the common or nightly lodging-houses. Some idea may be formed of the magnitude of the evil which the act was intended to counteract, when it is known that upwards of 100,000 people were lodged in the common nightly lodging-houses of London when the police first entered upon their duties under this act. This act has only been enforced in a few towns in the country; but where it has been put in force, it has been shown that, in proportion to their population, many of the towns of England are quite as bad as London. It is, however, an acknowledged fact, that wherever this act has been put in force, a great and manifest improvement has taken place in the character of the population affected by the provisions of this act.

The object of the second act, The Labouring Classes Lodging-Houses Act, was to encourage the building and establishment of lodging-houses properly constructed and carried on for the accommodation of the working-classes. This act was intended to supply decent and proper accommodation for those who were displaced by the provisions of the first act. At present, however, the local authorities have not availed themselves of the provisions of this act, except in a very few instances. It is to be hoped that this will not long be the case, and that when it comes to be better understood how much more expensive to the community are dirt, squalor, and moral degradation, than cleanliness, health, and morality, that the provisions of this act will be extensively put in force.

The next sanitary acts in point of date are those relating to the burial of the dead. In 1851 and 1852 acts were passed, the object of which was to prevent the burial of the dead in churches and chapels, and in burial-grounds surrounded by a dense population. The Metropolitan Interments Act, which not only interdicted interment in London, but provided a complicated system for the removal of the dead, and their burial in a large cemetery in the neighbourhood of London, was never carried into effect. But the evils of burying the dead in the midst of the living had become so notorious, and the practices of extortion on the

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1 In the city of London the powers given to the Commissioners of Sewers for the regulation of common and nightly lodging-houses are very extensive; for by the Sewers Acts of 1848 and 1851, the commissioners have control over all houses occupied by more than one family, any room of which is let for less than 3s. 6d. per week. This, indeed, is the definition of a common lodging-house in the City Acts of Parliament. part of those who undertook the management of funerals, that the Burial Act, simply forbidding the burial in towns and places of worship, has led to the most extensive reforms. Within the last ten years upwards of ten new cemeteries have been opened in the neighbourhood of London; and in almost every large town in the country similar provision has been made for the interment of the dead.

Amongst the individual sanitary evils against which the sanitary legislation of England has been directed is that of smoke. It is well known that smoke is composed of unconsumed particles of carbon, which, entering the atmosphere, fall down again, producing great uncleanliness, and leading to a practice of closing doors and windows, to the injury of health. Power was given to local bodies to diminish this evil in large towns under the Towns Improvement Clauses Consolidation Act. In some towns this power has been taken advantage of, whilst in others the principal manufacturers and producers of smoke have adopted the practical methods suggested for abating this nuisance. In 1813 a special act was passed, under the title of the Smoke Nuisance Abatement Act, in which powers were given to magistrates to fine those whose manufactories were complained of as producing smoke amounting to a nuisance. The application of this act to London has been attended with an immense improvement, although the smoke generated in private houses still produces a comparatively impure and murky atmosphere. Under the Local Government Act, it is competent for the local authorities in any town to introduce the Smoke Nuisance Abatement Act. A general introduction of this act, and the extension of its powers to the construction of fireplaces in private dwellings and workshops in towns, would be undoubtedly attended with increased cleanliness, and a greater attention to the ventilation of houses.

In 1855 the Nuisances Removal Acts of 1845 and 1848 were repealed, and the Nuisances Removal and Diseases Prevention Act was passed. This act, which is now in force, gives a legal definition of nuisances, which is as follows:—“Any premises in such a state as to be a nuisance or injurious to health.” “Any pool, ditch, gutter, watercourse, privy, urinal cesspool, drain, or ashpit, so foul as to be a nuisance or injurious to health.” “Any animal so kept as to be a nuisance or injurious to health.” “Any accumulation or deposit which is a nuisance or injurious to health.”

By means of these stringent definitions, a variety of causes of diseases are brought within the operation of the law. The local authorities can give notices for the removal of any nuisance; and if this is not attended to, a summons can be issued, and the offending parties brought before a magistrate. In certain cases also, where works are necessary to be done, the local bodies can do the work, and charge the person on whose premises the nuisance has existed. The duties of a medical officer of health and of a sanitary officer are also recognized; and these officers have power given them to inspect premises in cases where they suspect a nuisance to exist. The medical officers of health and sanitary inspectors have also powers given them under this act to inspect all articles of food exposed for sale which are suspected to be unfit for use as human food, and to seize the same, and bring the offender before the magistrate, who has power to inflict a fine upon the owner of the provisions thus seized.

A clause also, in the same act, gives power to the sanitary officers to inspect the premises of persons carrying on offensive and noxious trades, and to point out the best means of preventing any injurious influence being exercised upon the neighbourhood, and of appealing to the magistrate if their suggestions are not carried into effect.

A clause in this act goes so far to avert the evils which might arise from the operation of the Common Lodging-House Act, in driving people to private houses for their nightly lodging, as it regards the overcrowding of dwelling-rooms as a nuisance. In many parts of London, any room not allowing a space of 400 cubic feet to each individual habitually residing or sleeping in it is regarded as a nuisance, and brought under the operation of this act.

This act also contemplates the suppression of the unhealthy practice of dwelling in cellars or kitchens, and defines the conditions on which any room under the ground shall be allowed to be let as a residence. This act, though occasionally found too slow in its operations to remove an immediate and pressing cause of disease, has been found one of the most effectual of the various measures of English sanitary legislation for the permanent improvement of the health of towns. When it is considered that it deals with all those small causes of disease which are so constantly occurring in a civilized community, it is wonderful that its provisions are not more generally enforced. In any town or country district it would only be an act of benevolence on the part of the clergyman, the magistrate, the lawyer, or the medical man, to insist on its provisions being carried out in all cases where the manifest causes of disease exist.

Comprehensive and sufficient as the preceding legislative measures may appear to be, they are not based upon any comprehensive principle, and are deficient of any common basis of action. There are consequently constantly arising cases which require special legislation. London is an instance of this. The entire management of the sanitary condition of the city is confided to the corporation, whose acts date back to 1848; but as the city includes not more than a twentieth part of the metropolis, the health of the surrounding population had to be cared for in very various ways. It is not necessary here to enter into any account of the sanitary measures adopted in the metropolis under the various local boards and vestries. It will be sufficient to allude to the fact, that the city of London possesses local sanitary powers, which were put in force, under the control of a medical officer of health and sanitary inspectors, several years before the rest of London.

In 1857 the Metropolis Local Management Act was passed, which gave to all the parishes of London, with the exception of the City, the power of action in relation to sanitary matters. The management of the sewers, and various other powers in relation to the general condition of the metropolis, was vested in a metropolitan board of works, whose members were elected by the various vestries or local boards to whom the parochial management was confided. To the vestries or local boards are given powers to enforce all regulations connected with sanitary matters. One of the most important provisions of this act is the appointment of medical officers of health. Each vestry or board is required to appoint a duly-qualified medical man to fill this office. It is his duty to direct the operations of an inspector or inspectors of nuisances, who visit houses, workshops, manufactories, and other places where nuisances are either reported or suspected to exist. He sees to the ventilation of public buildings,—as churches, chapels, theatres, courts of law,—and obtains the sanction of the local board for all proceedings connected with the removal of nuisances. He receives from the registrar-general the weekly report of births and deaths in his parish; and by the latter he is guided to the existence of disease in his locality, which may require on that account special attention. The improvement that has taken place in London under the powers of this act has been very great; and the amount of negligence, with regard to the sources of disease, that has thus been revealed, is perfectly astonishing. At the same time, the local boards are not yet alive to the immense advantages to be derived from carrying out the provisions of In many instances the medical officer of health meets with no encouragement in the performance of his duties, and no regular system of inspection is prescribed to the inspectors of nuisances.

In this bill, no provision was made for dealing with the sanitary condition of the Thames. This great river, like other rivers flowing through towns, had been used from time immemorial as a receptacle for the refuse of the inhabitants on its banks. Moved by the daily access of the tide from the sea, and receiving upwards of 100 millions of gallons of water daily, for centuries the refuse poured into it produced little effect upon its purity. It was not till the extensive introduction of the water-closet system in London, and the abolition of cess-pools, with also the increase of gas and other manufactories on its banks, that the river began to give indications that it was receiving a larger quantity of decomposing matter than it could purify, or get rid of by its tidal movements. In 1856 it became apparent in the summer months that the river emitted a disagreeable stench. This became still more evident in 1857, and was obviously dependent on increased attention paid to the removal of all refuse from houses by the aid of drainage. In 1858 the stench again appeared with increased intensity, and was especially nauseous in the neighbourhood of the new houses of Parliament. Every one felt that special legislation was necessary to meet so gigantic an evil. This great river had become an elongated cess-pool, and the effect upon the teeming population of its banks might be, in the course of a short time, of the most disastrous kind. Accordingly, an act was passed in 1858, giving power to the Metropolitan Board of Works to commence works for the main drainage of the metropolis, and for preventing, as far as practicable, the sewage from passing into the Thames within the metropolis. It also gives them power to construct works on the shores and bed of the Thames; and empowers them to borrow for these purposes a sum of money not exceeding three millions. The works thus sanctioned are now in the progress of construction, and comprehend the complete drainage of an area of 117 square miles, and of houses calculated for the residence of a population of 3,500,000 people. These works are intended to carry separately the sewage of London down to a point of the Thames so far below the metropolis as not to interfere with the health or comfort of its inhabitants. The questions of deodorizing the sewage, or utilizing it, are purposely left open for the present. This improvement of the condition of the river will necessarily be followed by other arrangements. One of these is the embankment of the Thames, by which the scour of the river will be increased through London, a very necessary plan when it is remembered that 80,000,000 of gallons of sewage, which is now poured into the Thames above Blackwall, will be emptied into it at a much lower point. In connection with the completion of the system of main drainage, a plan has been proposed by Captain Fowke, by which any regurgitation of the sewage into the Thames passing through London would be effectually prevented. This consists in throwing a weir over the Thames below Greenwich, and cutting a canal with locks through the Isle of Dogs, so as to enable the traffic above the river to be carried on. This would relieve London of all difficulties from the tide, and give it a river of pure water, constantly at high-tide mark. If such a plan is not really open to objection, it would restore to London the river in more than its ancient purity, and which for bathing purposes and aquatic amusements would contribute greatly to the health of the metropolis.

Before closing this sketch of the sanitary legislation of England, we would refer to some of the minor acts which have been passed on subjects involving the public health.

From the time of the first discovery of vaccination as a means of preventing small-pox, enactments have been passed to secure the extension of the practice of vaccination. Obvious as is the benefit to be derived from this practice it has been greatly neglected, and recently a Vaccination Extension Act has been passed. By this act, all persons are required to have their children vaccinated within three months of their birth, under a penalty of ten pounds for neglect. It is, nevertheless, found that large numbers of persons allow their children to grow up without vaccination; and the result is, that there is always a fraction of the people susceptible of the ravages of this disease, and sufficient to keep it always smouldering and ready to break forth into a flame in all our city populations.

The slaughtering of animals in private houses, where there exists little or no proper accommodation, has always been regarded as a great nuisance, and an act has been passed for the better regulation of slaughter-houses, by which the local magistracy have power to refuse a license to persons slaughtering on their own premises. Although under this act licenses have been refused by the magistrates, yet, such is its deficiency, that it is well known in London that slaughtering takes place extensively without the granting of any license. It is hoped, however, that this act will lead local authorities to see the propriety of erecting abattoirs, or public slaughter-houses, for the accommodation of butchers, in which neither the food thus prepared nor the population of the neighbourhood will be in any way injured.

There are many other measures which have been adopted from time to time with a sanitary object in view; such as the introduction of lemon-juice into the navy as a preventive of scurvy, and the requiring the captains of merchant ships undertaking voyages of a certain length to have this article of diet on board for the use of the sailors. Since the revelations made by the Crimean war of the utter deficiency of all our military arrangements to secure the proper health of our soldiers, the whole subject of the sanitary condition of the army has been inquired into by a commission appointed by Parliament, whose report has revealed a deficiency of sanitary arrangements in our barracks, and in the management of our soldiers, that could be equalled only in the most neglected and miserable parts of the population of our large towns. The same evils have been found to exist in our Indian army, and amongst the regiments in our colonies. Almost all arrangements, whether of food, clothing, or shelter, have been found to have been made in ignorance of vital laws, and in defiance of the experience of civilians.

In this brief sketch of English legislation in relation to sanitary science it will be seen that, although much has been done, much more remains to be done. The subject of public health has been treated piecemeal, and no general organization for sanitary purposes exists. The subject, though one lying at the very foundation of human society, has not attracted public attention to the extent which its importance demands. Neither the legislator nor the lawyer, the magistrate nor the medical man, are instructed in the principles of sanitary science. Although professorships of hygiene exist in the universities of the Continent, no public recognition of this subject as a branch of education has taken place in Great Britain. It is still an object worthy the attention of our legislature, to place sanitary science in such a position that it may confer on the community all the advantages which a knowledge of its principles, and their practical application in daily life, is calculated to confer. PART I.—GENERAL HYGIENE.

The department of general hygiene embraces a knowledge of the laws which regulate the existence of the human being, and may be divided into three sections: first, the consideration of individual differences and peculiarities; second, of those external agents and internal functions on which the life of the individual depends; and third, the influence of especial morbid agents, as the poisons of infectious and contagious diseases.

1. INDIVIDUAL PECULIARITY.

When mankind is regarded as a whole, we find that the external agents by which man is surrounded act very differently on different groups of the human family; and on a closer investigation of the causes of this difference, we find it can be referred to individual peculiarity. In any application of hygienic rules, it is of the utmost importance to keep these peculiarities and differences in view. The conditions which would ensure the health of the Englishman are not applicable to the Esquimaux or the Hindu; and the varying temperaments, ages, idiosyncrasies, hereditary tendencies, habits, and constitutions of individuals must always be considered.

Race.—The question of whether the races of men have been produced as the result of circumstances, or whether they have been born with their peculiarities stamped upon them, is still perhaps an open one with ethnologists; but for the hygienologist the great fact is evident, that there are different races of men, on whom external agents act very differently. This is a question of considerable importance, and has not hitherto obtained the attention to which it is entitled. The races inhabiting the central and northern parts of Europe will not bear the heat of tropical climates with the same impunity as the Asiatic and African races, born and nurtured within the tropics; whilst the inhabitants of these countries require much warmer clothing for their health when in the temperate or colder regions of the earth than the natives of the same districts. How far this is connected with the special susceptibilities of particular tribes is a matter of highly interesting inquiry.

Temperament.—Next to race, we may reckon the influence of what is called temperament. Three well-marked forms of temperament have been recognised by all medical and physiological writers. These are respectively called the nervous, the sanguine, and the lymphatic. To these some add a bilious or melancholic temperament; whilst medical writers recognise diatheses as the scrofulous and rheumatic. At any rate, persons with the distinguishing features of these temperaments exhibit very different tendencies with respect to disease. The circumstances that would quickly produce special forms of disease in one class will not affect another at all. Thus, taking the two latter conditions of the system, the scrofulous and rheumatic, as examples, it is found that a variety of circumstances will produce an outbreak of scrofula or rheumatism in these two general conditions of the system which will not in those conditions of the system where their signs are not present. In the application, then, of hygienic rules, it should always be remembered that what will produce disease in persons of one temperament will not in another. And, again, the same cause may in two persons of different temperaments produce different kinds of disease.

Idiosyncrasy.—Persons of all temperaments may have peculiar relations to external circumstances. Thus, where the tendency is to the production of the same disease under the same circumstances, it is called an idiosyncrasy. Some persons faint at the sight of blood. Others vomit under peculiar odours. Some contract febrile disorders wherever exposed to their special contagions. These cases require consideration in the application of hygienic rules, General care should be taken not to draw a general inference from the experience of individuals thus constituted.

Age.—This is a most important element in all hygienic considerations. The infant is much more susceptible of injurious agencies than the youth or the adult. Nearly half the population of our large towns dies before it is five years old. This death is, however, unnatural. Much of it might be prevented by a knowledge on the part of the community of the laws which regulate the life of children, as compared with that of adults. Children are improperly fed, nursed, housed, and clothed; and the consequence is, they die. They require different food from adults; they are more susceptible of cold, of the action of poisons, and of a variety of morbid agencies; and until greater attention is paid to their special relations to external agencies, the sad tale of our annual bills of mortality will be told. The injurious effect of this mortality is not limited to the destruction of life. Where one child dies, ten are taken ill from the same causes, and recover. The cost of illness is thus added to that of death. But the evil does not end here. Half of the life thus lost is lost before it is twelve months old. The mother, instead of healthfully nursing her offspring, becomes again pregnant; and in this way a permanent effect is produced on the age of the whole population, as those who struggle through become a younger population than if their elder brothers and sisters had lived. Where the mortality amongst children is greatest, there the average age of the population is least. This reduces the working power of a population, and renders it less able to enter upon those occupations by which food is produced, money realized, and wealth accumulated.

What is true of infancy is also true to a limited extent of childhood and youth. In the period from three to fifteen and twenty years of age, young persons are not able to resist the causes of disease so well as those who are older. The young men in our armies suffer more than the middle-aged from exposure and fatigue.

Whilst the young from twenty to the middle age at forty-five are best able to resist the external causes of disease, it should be remembered that the poison of typhus and typhoid fevers seems to act more vigorously on those of middle age than at any other period of life.

The peculiarities of old age are almost as marked as those of infancy. Diseases of deficient or decayed nutrition come on; and the circumstances of the aged require especial consideration in the adaptation of hygienic rules.

In the special applications of the laws of sanitary science to the prevention of disease, sex, hereditary tendencies, acquired habits, and morbid dispositions, must always enter into consideration.

2. AGENTS INFLUENCING LIFE.

(A.) External Agents.

The distinction between external agents which influence life, and the organs by which the functions of life are performed, is not easily made. When we examine a vegetable or animal body, with a view to ascertain the nature of its vital processes, it is difficult to say where the chemical and physical forces end, and the vital ones commence. For practical purposes, however, we may speak of certain chemical and physical agencies as external to the human body, as the air, the soil, and water; and of certain others as acting more intimately on the organs of the body, and undergoing changes in them as internal agencies, as the food from which is formed the blood, and of the secretions which are got rid of from the blood by the aid of the various glands of the body. It is obvious that the consideration of these subjects belongs to physiology; and all that the writer on hygiene has to do is to point out the practical bearing of these subjects on the preservation of health.

Light.—Of the great forces which are continually in action in nature, light is one of the most important. By its chemical action on the vegetable cell, it converts the elements of carbonic acid and ammonia into the various compounds which form the great variety of vegetable products, and more especially those which yield food to man and the animal kingdom. In proportion as light is withdrawn, vegetation dwindles; and as light acts, it is profusely developed. This is seen as we proceed from the poles to the equator on the surface of the earth. The direct action of light on man and animals has not been so well ascertained. There can be no doubt, however, that light exercises a favourable action on human health. We may, indeed, infer that, to a limited extent, the same changes go on in certain of the animal tissues which are so characteristic of the vegetable, and that these may contribute to the healthy development of the organs of the body. No definite conclusions can be arrived at from the experience of those who live in mines and caverns, away from the light of day, as so many other unhealthy circumstances prevail in such places. But of the cheerful influence of light on the mind there can be no doubt; and in all cases as much light should be admitted into buildings as should enable persons to feel its exhilarating influence.

Heat.—This force, which in a large number of instances is co-existent with light, exerts a powerful influence on vegetation, but is still more remarkable in its effects on animals and man. Without heat, light would not act beneficially on plants. Without certain degrees of heat, animals and man cannot exist. The tissues of most plants are destroyed at a temperature below 32° Fahr.; and although the germs of both plants and animals will for a certain time resist a temperature much below this, no growth takes place at such temperature. The vegetable world disappears as it were as the temperature passes from below 60° to the freezing-point. This also is the case with the great mass of the lower animals. But in the higher animals, provision is made for the maintenance of their temperature independent of that of the atmosphere. Thus man, under all circumstances, has a temperature of 98°. It is the due maintenance of this temperature that makes his relation to external heat an object of hygienic rules. If the external temperature is low, then the object must be to prevent such an amount of diminution of the internal heat as would lead to disease. This is done in two ways: first, by increasing the heat-producing food which is daily consumed; and second, by diminishing the loss of heat from the surface by warm clothing or the production of an artificially-warmed atmosphere. It is not often that the external temperature rises to the height of that of the body; but in proportion as it rises above 60° or 63° an impression of warmth is produced on the body, and the necessity for cooling processes is produced. Clothing needs to be reduced in quantity; a moving atmosphere must be substituted for an artificially-warmed one; and as the heat increases, the application of cold to the surface should be had recourse to. This latter object is best effected by means of cold bathing.

Electricity.—The electrical force is frequently disturbed in the atmosphere and on the surface of the earth. Plants and animals partake of this disturbance, and in the case of the manifestation of free electricity, present the usual signs of positive or negative electricity. Although many elaborate efforts have been made to connect morbid tendencies, diseases, and even the outbreak of epidemic diseases, to the action of electricity, at present the evidence is wanting to show that any condition of terrestrial electricity acts as a cause of general disease. In those states of the atmosphere where electricity is developed, other phenomena are generally present, to which may be ascribed the effects usually attributed to electricity. It is sufficient to say here, that at present we know little or nothing of the agency of electricity in the production of disease. The only subject in connection with electricity which demands attention on the ground of public safety is that of preserving life and property from destruction by the aid of lightning-conductors.

The Atmosphere.—The great aerial ocean which surrounds the world is necessary to the existence of both animals and plants. It is subject to considerable chemical and physical variations, which affect more or less the health of man. It is also the medium for the diffusion of those poisons which, either arising from decomposing animal or vegetable matter, or the diseased body of man, produce those forms of zymotic disease which are most destructive of human life.

Atmospheric air consists principally of oxygen and nitrogen; with these are mixed aqueous vapour and carbonic acid. Of these constituents, oxygen is the most important, as by its agency many of the functions of animal life are carried on. The oxygen unites with the carbon of the food in the blood of animals, and the result is the formation of carbonic acid and the evolution of heat. Where atmospheres have their composition altered by artificial means, as in overcrowded rooms, the reduction of the quantity of oxygen acts injuriously on the system, by diminishing the oxidising processes which are going on in the system.

Oxygen assumes two forms in the atmosphere, one of which is called ozone. This latter form, of ozone, is not always present, but is sometimes very abundant. Ozone is a more active form of oxygen gas. It readily unites with the combustible elements, and appears to be the great agent for reducing those compounds arising from decomposing vegetable and animal matters in the air which would otherwise be injurious to health. In the same way, it acts beneficially on the human system, by quickening those processes of oxidation which are essential to health.

Ozone is tested for by the property it possesses of decomposing iodide of potassium, uniting with the potassium and setting free the iodine, the presence of which may be detected by the agency of starch. Thus, test-papers saturated with a solution of iodide of potassium and starch are employed to denote the presence of ozone. Ozone is found abundantly in air coming from the ocean, and in mountainous and rural districts free from vegetable and animal decomposition. It is seldom found in the air of London or our large towns. When found, it is in the suburbs, and when the wind is blowing from the sea or the country towards the city. The consideration of the presence and agency of ozone is one demanding further consideration.

The quantity of moisture contained in the atmosphere varies, and exercises an important influence on the functions of life. The quantity of moisture that can be taken up into the atmosphere depends upon the temperature. As a rule, the higher the temperature the larger the quantity of moisture. At the same time, the quantity of moisture in the atmosphere varies with a number of circumstances, as the time of the day and the year, height above the sea-level, prevailing winds, &c. The quantity of moisture in the air affects considerably the transpiration of water from the human body through the skin and lungs. When the atmosphere is moist, the rapidity with which transpiration is performed in the human body is much less than in a dry atmosphere.

The quantity of moisture in the atmosphere differs much in different places; and it becomes frequently a matter of practical importance, in the location of houses, for families to ascertain what is the prevailing amount of moisture in the atmosphere. There is abundant evidence to show that an excess of moisture in the atmosphere above the average is injurious to health. It diminishes the changes which go in the body, and leads to diseases of low vitality. On the other hand, a very dry atmosphere is found to stimulate the action of the skin and lungs, and to bring with it a train of disorders, which are removed or relieved by a change to a humid atmosphere.

The influence of heat and moisture combined requires consideration; a moist atmosphere with a low temperature produces different effects from a moist atmosphere with a high heat. The latter conditions are especially productive of disease amongst the European nations, whilst the former conditions are destructive of the life of those races of people who live in tropical climates.

In England the hottest months of the year are the most unhealthy, and this unhealthiness is increased if the atmosphere is unusually moist. The next most unhealthy portion of the year is the cold months; and the public health suffers more if an unusually moist atmosphere prevails.

The carbonic acid naturally contained in the atmosphere is the result of the oxidating processes that go on on the earth's surface, as the respiration of animals, the decomposition of dead animal and vegetable tissues, the combustion of carbon, and the evolution of gases from springs and volcanoes in the bowels of the earth. In this quantity it is the food of plants, and is perfectly uninjurious to man and the animal kingdom. This gas, however, is constantly liable to increase in the atmosphere, when the products of combustion or respiration are prevented from finding their way into the great bulk of the air. This is the case in houses and places of public assemblage, rendering ventilation necessary. The evidence of the injurious effects of an increased quantity of carbonic acid in the atmosphere is very decisive. Not only have we proof that life may be destroyed by its presence, as in the case of the prisoners in the Black Hole of Calcutta, but also proof that an atmosphere vitiated with it to an extent in which no immediate injurious effects are produced will produce the most destructive effects on the system. A large amount of scrofula and phthisis is dependent simply on the depressing agency of this gas in sleeping and other apartments, where people spend a great portion of their lives. A great social sanitary work has yet to be done, in calling the attention of the public to the danger of living in rooms in which the carbonic acid from respiration and combustion is not freely got rid of.

The pressure of the atmosphere exercises an influence on the life and health of man. The dwellers in valleys, or in districts on a level with the sea, experience a greater amount of atmospheric pressure than those who live on hills and mountains, or at heights above the level of the sea. The pressure of the atmosphere differs also in the same place, and at different seasons of the year and times of the day. It has been observed that epidemic and pestilential diseases are connected with an unusually dense condition of the atmosphere. During the prevalence of cholera in this country in 1832, in 1849, and 1854, the barometer indicated the highest amount of pressure in the atmosphere during the period.

A diminution in the pressure of the atmosphere is attended with congestion of the capillaries, and copious perspiration and apoplectic seizures; and sudden deaths occur as the result of this condition of the capillary circulation.

A rapid movement of the atmosphere is attended with a diminution of its pressure. In this way, winds act mechanically on the health.

Winds also act on the health according to the direction in which they blow. They are hot and cold, moist and dry. In this country they exercise a very marked influence on health and life. The north is dry and cold, and prevails in the middle of winter. Wet northerly winds give rise to diarrhoea and disturbance of the digestive organs. The north-east wind is cold, and sharp, and dry. It is attended with little moisture in the atmosphere, and accompanies the driest weather. The east wind is dry and cold. The prevalence of these winds produces great fatality amongst phthisical patients. They are accompanied with a peculiar form of dyspepsia, which tends to develop rheumatism and gout. The east wind seldom gives any indications of the presence of ozone.

The south-east wind is a moist and cold wind, and is almost invariably accompanied with rain in this climate. It contains a considerable amount of ozone. Diarrhoea, cholera, coryzae, dysentery, and bronchitis prevail with this wind.

The south wind is generally accompanied with rain and an elevated temperature. It affords the greatest quantity of ozone; and although highly favourable to the longevity of phthisical persons, produces catarrhs and bronchitis.

The south-west, west, and north-west winds are all more or less favourable to health. They come to this country more or less charged with the pure air of the Atlantic; and although accompanied with rains and storms, do not appear to act injuriously on man.

It will be seen that it is an important thing, in fixing on the localities of towns and houses, to regard protection from prevailing winds. In other parts of the world particular winds prevail, as the sirocco and the sirocco, whose effects on life and health are very destructive.

An absence of wind is a state of the atmosphere in which the greatest pressure of the barometer is likely to occur, and in which the influence of corrupting and putrefying agents in the atmosphere is most likely to be felt. During the prevalence and preceding the breaking out of great epidemics, unusual stillness of the atmosphere has prevailed. This was observed in the great plague of London in 1665, and also during the prevalence of the three great cholera epidemics in England.

The atmosphere also requires study from the sanitarian, on account of its being the medium through which poisons are frequently introduced to the human body. Mineral particles of all kinds may be conveyed through the air. Thus, in trades producing dense powders, such substances are conveyed through the air, and introduced into the lungs, thus becoming sources of disease; as in the steel-dust of the knife-grinder, the coal-dust of the miner, &c. The fumes of mercury, phosphorus, sulphur, arsenic, and other substances used in the arts, are thus conveyed to the artisan; so also injurious gases, as sulphuretted hydrogen, carbonic acid, carbonic oxide, &c. It is the law of vegetable and animal compounds that their elements shall return to their simpler compounds by putrescence and decay. The elements thus combining and forming compounds which escape into the atmosphere are carbon, hydrogen, nitrogen, oxygen, sulphur, and phosphorus. Many of the gases thus formed are very injurious to human health. The form, however, in which animal and vegetable matters appear to be most injurious in the atmosphere is that of a tendency to change before the ultimate compounds are formed. In this state vegetable and animal matter is capable of establishing in living bodies states of change in their tissues similar to that in which they themselves are. These bodies thus act as ferments. In some states of the atmosphere these substances, of whatever nature they may be, are much more readily conveyed than in others. As a rule, hot, moist, and still conditions of the atmosphere favour the conveyance of these particles of matter. Hence it is, when all these conditions combine, that zymotic diseases prevail most.

Water.—In the form of vapour, water has most important relations to life, as we have seen in the preceding section; but in the condition of liquid water it sustains other relations of equal importance. Water is necessary to man as a civilized being, but naturally he uses it for cleaning and washing, and takes it internally with his food. In all these relations it is of great importance that the water he uses should be free from impurities which are likely to engender disease. The first great source of water is the ocean, which being carried into the air in the form of vapour, is again precipitated on the earth in the form of snow, or rain, or dew. The water that falls on the earth is, part of it, carried off in the form of rivers back to the sea, and another portion enters the earth, and comes again to the surface in the form of springs. Thus we have naturally sea-water, river-water, and spring-water. The latter is constantly impregnated with mineral constituents; and when these are very obvious, the waters are called mineral. If the water comes to the surface of the earth with a greater heat than natural, it is called thermal. Sea-water is unfit for dietetical purposes, on account of the large quantity of salt it contains. This does not, however, prevent its being used for the purpose of bathing, in which the object is the application of cold to the skin. The exercise of swimming is more easily performed in salt than fresh water, and the stimulant effect of the salt appears to exercise a healthy influence on the capillary circulation. In cases where it is desirable, it should be known that pure water can be obtained from the distillation of sea-water.

River and spring waters are those which are mostly employed for washing and dietetical purposes. These waters seldom contain so large a quantity of saline matter as seawater. The saline matters may, however, be in quantities to render them unfit for either washing or drinking. Where the saline constituents interfere with the action of soap, they are objectionable for washing purposes. When the saline constituents are similar to those found in the blood, they do not appear to exercise an injurious influence for dietetical purposes, unless they are in great excess.

All waters are liable to contamination, from the presence of decomposing animal and vegetable matters. The existence of large bodies of water containing such matters is frequently prejudicial to health. Lakes, ponds, bogs, and stagnant waters generally, are liable to this contamination, and the effluvia they give off produce diseases of various kinds, more especially intermittent and remittent fevers. Rivers into which the refuse of towns is poured are liable to this contamination, and are thus not only rendered injurious for drinking purposes, but detrimental to those who live on their banks.

Spring or well waters are exposed to these contaminations. In towns, where the soil is permeated with the contents of cesspools or the leakage of drains, the wells may be contaminated, and the water thus rendered entirely unfit for use. Extensive evidence has been brought forward to show that attacks of epidemic cholera have been connected with the contamination of well and river waters used for dietetical purposes. Such waters may be rendered comparatively sweet by boiling, filtering, and other cleansing processes.

Soil.—The geological strata under the soil exercise a considerable influence on the life of plants and animals. These strata frequently determine the composition of the waters which are drunk and used. They vary in chemical composition and physical properties, and have varying relations to heat and moisture. Some soils absorb heat, and keep up the temperature of a district. This is the case more or less with sandy, gravelly soils. Such soils do not retain moisture; and as moisture is necessary to animal and vegetable growth and decomposition, they are more free from malarious and continued fevers, and neuralgia, than other soils.

A clay soil retains moisture, and is always damp. On this account it encourages animal and vegetable growth and decomposition. It is drained with difficulty, and is rendered colder by the amount of moisture it contains. Mists and fogs are more likely to occur on moist clay soils than on dry gravelly ones.

Limestone and sandstone soils heat or cool very rapidly. At the same time, they do not allow water to pass off very rapidly; and by retaining animal and vegetable matter, they are liable to generate poisonous miasmas during the heat of summer.

Chalk, like gravel, allows the free percolation of water, and does not rapidly absorb heat. It absorbs moisture, and the atmosphere is dry over it. Next to a gravelly soil, a chalk soil may be regarded as most healthy. There are many combinations of soil which need to be looked to in providing for the sanitary welfare of those who live upon them.

(B.) Internal Agents.

Another set of agencies are those which act more directly on the functions of the body, and which may be generally included under the heads of food, clothing, exercise, and mental and moral culture.

Food.—The human body, like other organisms, is composed of material elements. These are about eighteen in number. Four of these—carbon, hydrogen, nitrogen, and oxygen—are called organic elements, on account of their universal presence in living organized bodies. Two—sulphur and phosphorus—are very generally present, and are called pseudorganic elements. The rest are inorganic elements, and consist of the non-metallic elements, chlorine, iodine, and silicon; and the metals, potassium, calcium, sodium, magnesium, iron, and three or four others occasionally present.

These elements exist in compounds which form the tissues of the body. They are generally introduced into the body in the form in which they are found there. These compounds are found in the mineral, vegetable, and animal world; and when consumed by the animal, are called food. Food subserves two principal purposes in the system of animals: 1. It builds up the fabric of the body; 2. It maintains its special animal heat.

For the performance of these two great functions, special compounds are adapted. Thus, water, the compounds of the inorganic elements, and the nitrogenous compounds of plants, are employed for the performance of the first function; and starch, oils, and sugar for the second. There are, however, certain compounds consumed especially by man which act more particularly on the nervous system, as tea, coffee, alcohol, and tobacco, which may be called medicinal or auxiliary food. The food of man, with the exception of water and salt, is mostly derived from the vegetable kingdom. It is the plant which acts upon the organic elements in such a manner as to form fit compounds for the tissues of animals. The following outline of the food of man will afford an idea of its nature and relations to his life:

1. Alimentary or necessary, which may be divided into three principal groups. 1. Mineral. a. Water. Taken pure and in various beverages, and also contained largely in solid food. b. Salt. Found largely in the ashes of all vegetable and animal food, and includes also common salt. 2. Nitrogenous: nutritious or flesh-forming food. a. Albumen. Found in eggs, blood, and nervous tissue of animals, and in the juices of many plants. b. Fibre, also known as gluten. Found in the muscles of animals, and in the grains of the various cereal plants, as wheat, barley, maize, rice, &c. c. Casein or legumen. Found in the milk of the Mammalia, and separated as cheese, and also in the seeds of leguminous plants. 3. Carbonaceous: respiratory or combustible foods. a. Starch. Found in almost all vegetable foods; and is pure in sago, tapioca, and arrow-root. Another important practical question in relation to public health is the adulteration and sale of impure food. This question has recently received the attention of the legislature, and more stringent measures are likely to be taken for the suppression of these practices. That the adulteration of food is carried to an injurious extent has been sufficiently proved; whilst through ignorance persons frequently sell food in a state likely to produce disease.

Clothing.—In a civilized state, man clothes himself, and by this means saves a large amount of wear and tear in the system. In cold and temperate climates, exposure naked to cold would destroy a vast amount of young life at once, and lead to the early destruction of mature life. At the same time, the surface of the body requires a certain amount of cooling in the hotter seasons of the year; so that the subject of clothing is one of considerable importance in a sanitary point of view.

Children are more influenced by cold than adults, and should be warmly clothed whenever the temperature is below 60° Fahrenheit. To a neglect of this rule may be traced the destruction of a large amount of infant life in this country. Neither the chest nor the legs of young children are sufficiently clothed in winter. Women also dress too lightly about the chest in the winter of these climates. Hence their liability to bronchitic attacks. In dressing, it should be remembered that all clothing made of animal substances is warmer than that made of vegetable fabrics. The head is naturally clothed, and needs perhaps less attention than it receives. If warm clothing is needed in cold climates and weather, it becomes oppressive in hot climates and weather. As the temperature rises above 65°, woollen clothing of all kinds may be exchanged for cotton and linen. The custom of clothing European troops in their woollen dresses, and hot and heavy head-dresses, in hot and tropical climates, is opposed to reason, and exceedingly destructive of health. The colour of clothes is also of importance. Economy dictates dark colours as showing the dirt less; but dark colours absorb heat in the summer when it is not wanted, and radiate heat in the winter when it needs to be husbanded. White and light-coloured clothing is that which is best adapted for clothing at all seasons and in all climates of the world.

Exercise.—The calling into play the action of the voluntary muscles is called exercise. The contraction of the muscular tissue is attended with the destruction of a certain amount of the particles of which it is composed. This renders a restorative necessary, the blood is drawn upon for new matters, the capillary circulation is increased in the muscles moving, a corresponding increase of action takes place in the capillaries of the lungs, the inspiration becomes deeper and more frequent, the heart is stimulated to action, and the circulation of the blood is more rapid in every part of the body; the secreting surfaces are more active, the skin perspires, the exhalation of carbonic acid and moisture from the lungs is greater, and the whole system sustains an increase of activity. Of course such effects are more or less extensive according to the nature of the exercise. It may be of so violent a kind as to embarrass the heart and lungs, and where these organs are weak or damaged death may ensue. Health is, however, connected with a due exercise of all the muscles. In many trades, particular sets of muscles are called into action to the exclusion of others. The want of exercise in the latter may be productive of disease. The excessive exertion of the voluntary muscles in laborious occupations tends to waste the system and destroy life; whilst a life of freedom from muscular exertion permits the degradation of the tissues of the body, and an accumulation of fatty matter, which invites the attacks of disease or ends in sudden death.

To diminish the destruction of life by over-exertion, and to supply such exercises as will maintain health, are the objects of the sanitarian. When the occupation does not involve a sufficient amount of exercise, the movements of the body involved in walking, running, jumping, riding, driving, rowing, swimming, fencing, declaiming, and reading aloud, may be recommended. A regular system of gymnastic exercises may be adopted with advantage in schools. For the sedentary classes of our artisans and commercial population public play-grounds are strongly to be recommended, in which games and exercises might be engaged in and adapted to the special wants of those using them.

Connected with exercise is the subject of rest. The voluntary muscular system, and the nervous system through which it acts, need rest. Continuous voluntary exertion exhausts more than the same amount of labour with rest. Periods of hard work and exercise should be intermitted with periods of cessation from exertion. This applies also to mental labour. Nature secures a certain amount of rest during meals; but the grand rest of the system is sleep. During the period of infantile and youthful excitability, sleep needs to be of longer duration than with the adult. For man in his vigour a certain amount of sleep is essential to his well-being. Thousands die for want of sleep, produced either by anxiety or a determination to shorten the hours of repose. As a rule, it may be said that the healthy hard-working man requires, in every twenty-four hours, eight hours in bed. Many can do with less, but none will ever repent securing this amount of rest. Some even require nine. Persons may go on for years despising this rule, but in the end the nervous system exacts from those who over-work it a fearful penalty.

Mental and Moral Culture.—The special functions of the brain and nervous system require attention from those who would preserve the health of the human body. What is true of any other general function is true here; a partial or excessive culture of the functions of the nervous system is likely to engender disease. Unless there is a harmonious development of the perceptive and reflective powers, and a proper development of the will, the human being is subject to the control of passions and feelings which lead to the most destructive effects upon the rest of the system. The neglect of the rules of sanitary science, seen in the destruction of thousands and tens of thousands of lives annually, points to the necessity of intellectual culture for the safety of the race; whilst the records of insanity and crime show how painfully society pays for the neglect of a proper culture of the moral and emotional nature of man.

3. SPECIAL MORBID AGENCIES.

The human body is liable to certain specific forms of disease, arising from the introduction into the blood from without of certain substances which act as poisons. As a rule, mineral substances, which are not naturally contained in the human body, act as poisons. These substances are often used for the purposes of suicide and murder. They are not, however, placed in the category of substances producing specific diseases. Such substances are produced either in the living tissues of plants and animals, or result from their decomposition. Such poisons may be divided into those generated in the bodies of living animals and plants, and those produced by vegetable and animal decomposition. Those generated in the living animal body may be divided into those produced in the human body, and those produced in the lower animals. Amongst the latter poisons may be enumerated those produced in the dog in hydrophobia, and in the horse in glanders.

Amongst the poisons generated in the human body may be mentioned those of syphilis, small-pox, scarlet fever, measles, diphtheria, typhus fever, typhoid fever, plague, hooping-cough, and cholera. In these instances the system has the power of generating a poison which, when brought in contact with another human body, is capable of inducing in it the same form of disease as that in which itself was produced.

We may here pass over the consideration of poisons produced in living plants, as they are only accidentally or designedly introduced into the system.

Dead animal and vegetable matters are capable of entering into a state of decomposition, in which they may be taken into the body as food, or in which their particles may be diffused through the air, and thus introduced by the agency of the lungs into the blood. Such poisons, under the names of malaria and miasmata, are known to be capable of inducing disease in the human body.

All these poisons are more or less under the control of human agency. Where the poisons generated in the human body prevail, there strict quarantine, or measures for diluting the poison, do not fail to prevent the spread of disease. In the case of the putrid poisons, the removal of the cause, or the removal of persons from their influence, is known to avert disease.

In considering the action of these poisons, and the best means of rendering them inert, three things should be borne in mind: 1. The body attacked, or likely to be attacked; 2. The medium through which the poison is transmitted; 3. The poison itself.

With regard to the human being, it should always be recollected, with regard to all these poisons, that some persons are highly susceptible of their action, or predisposed to receive them, whilst others present none of this susceptibility or predisposition. A person vaccinated, or who has had the small-pox, will not contract small-pox on exposure to the contagion. It is no proof of the non-contagiousness of a disease that all persons exposed to its action do not acquire the disease. The subject of the causes that render some persons liable to take certain diseases, and others not, is worthy all attention, as tending to throw light on the spread and propagation of contagious diseases. Some of the diseases referred to are only propagated by contact with the diseased body, as syphilis and hydrophobia; but the majority of them are propagated by the poisonous matters passing through the atmosphere. This is a point of great practical importance. Still and moist states of the atmosphere are those which most favour the passage of poisonous gases. Currents of air will, however, convey the poison to a distance. The more concentrated the poison is in the atmosphere, the more likely it is to communicate disease. Infection may be avoided by the current being carried away from an exposed body; and the poison may be so diluted as not to produce an impression on even a predisposed body.

The nature of the poison differs. In some instances it is so intense that a small quantity will reproduce the disease in a predisposed body, whilst in others free exposure is required. As instances of intense poison, those of scarlet fever and small-pox may be given; whilst the poison of cholera and typhoid fever are of a much less intense kind.

Poisons seem to differ at different times and seasons. They are much more vigorous at the breaking out of an epidemic than at its close. They sometimes are so feeble that individual cases occur, and no spread of the disease results; at other times it would appear that diseases become epidemic from assuming a poisonous activity that ordinarily do not present this phenomenon. Thus, under some circumstances erysipelas and dysentery become highly contagious, whilst in their ordinary forms they exhibit no tendency to spread. It would even appear that diseased germs are susceptible of transformation; that at one period they shall produce one form of disease, and at another time another. These points are most important to bear in mind in dealing PART II.—SPECIAL OR PARTICULAR HYGIENE.

It is not enough to inquire into the general laws of vitality, or to ascertain what are the necessary conditions of health and comfort, but an application of this knowledge must be made to the various sanitary wants of a community, and to the hygienic demands of industry. This is the aim of practical and especial hygiene. It has for its objects a minute acquaintance with the habits and occupations of the people, a particular knowledge of all the circumstances affecting the health of a community, and the application of rules and remedies to the many unwholesome influences that spring out of a social existence. It takes cognisance of the geographical situation of towns, the arrangement of streets, the construction of houses, the cleansing of the public way, the supply of pure water, the burial of the dead, and the removal of all corrupting refuse. It also concerns itself with the adulterations of food, the unwholesome influences of trade, and the injuries to which labour is exposed. All these, therefore, will form the subjects of consideration.

CHAP. I.—THE SITUATION AND CONSTRUCTION OF HOUSES.

Although these are matters of great importance, in a sanitary point of view, yet they receive but little attention from builders and architects; in fact, the condition of our towns, and the way in which cities are enlarged and remodelled, show that hardly a thought is bestowed on the advantages of situation, or on the general arrangement of streets; and in respect of the houses themselves, they are characterised by a showy exterior rather than by any design for internal comfort. In most cases the rooms are low and badly constructed for warmth and ventilation; the walls are composed of materials that offer but slight resistance to damp and cold; the windows are small, and so badly situated as to give no facilities for the admission of light and air; the passages are dark and narrow; and the whole fabric is cheerless and uncomfortable. Besides which, the houses are crowded together, and tower up to an unnecessary height. They thus darken the narrow and crooked thoroughfares; and are arranged without regard to the direction of the light or the course of the wind; in fact, it would almost seem as if every effort had been made to bar out the wholesome influences of nature. All this tells upon the vigour of the population; for it not only shortens life and engenders diseases of a low type, but it also saps the strength of the community, and more than decimates the infant population.

Again, it too often happens that the poor are lodged in the dilapidated houses of the rich, where it is impossible to secure for them the appliances which are necessary for health and comfort. A large share of the immorality and disease of our large cities is due to this, and to the indiscriminate association of the sexes which such a condition of things is sure to encourage.

It is not possible, however, to discuss in this place the several details of such an inquiry; and therefore we must be content with an exposition of the general principles of the subject. That which should be aimed at in the construction of our dwellings is—

1. The selection of a locality which is not in itself unwholesome, as from the proximity of marshy ground or stagnant water. It should not be so elevated as to be exposed to undue cold, nor so low as to be deprived of the salutary influences of a dry and bracing atmosphere.

2. The ground should be firm, dry, and porous; and it should permit of easy and natural drainage. A damp clay soil is especially objectionable, and so also is a wet and peaty humus; for both of them provoke diseases of a malarious type.

3. The aspect of the building should allow a free access of air and light; and the principal windows should be so placed as to receive the direct rays of the sun, and to transmit a current of air that may sweep through the house when it is needed.

4. The walls should be constructed of materials that do not retain damp or organic impurity.

5. The houses should stand apart whenever it is possible.

And

6. The streets should be arranged so as to receive the sun's light, and be open to a free current of air.

CHAP. II.—ON THE WARMING OF BUILDINGS, &c.

Warming of Buildings.—As the ventilation of buildings will be found treated in another place in this work (see Ventilation), nothing requires to be said of it here. This chapter shall therefore be devoted to the warming of buildings, &c. The circumstances which render this necessary are the entrance of cold air by the doors and windows, the conducting power of the walls, and the radiation of heat from the glass of the windows. The walls are generally from two to four degrees below the mean temperature of the room, and they absorb and conduct a large amount of heat. The cooling effect of glass is also very great; for a square foot of glass will generally cool about 1/3 cubic feet of air per minute from the mean temperature of the room to that of the external air, and the cooling effect of metal or corrugated iron is nearly the same. Taking these facts into consideration, the rule which is generally adopted for maintaining the warmth of a room or public building at a genial temperature of from 60° to 65° is, that the supply in cubic feet of warm air at this temperature should be equal to four times the number of people the room is intended to contain, added to eleven times the number of external doors and windows, added to 1/3 times the area of the exposed glass. If the windows are double, the radiations may be neglected; and if they are tight, there is no necessity to multiply them by eleven; for in these cases the provision or supply is simply for ventilation.

The means which have been adopted for effecting this are the open fire, the close stove, the system of flues for hot air, and the closed pipes for a current of steam or hot water.

Although the open fire is not an economical way of warming a room, yet it is generally adopted in this country because of its cheerful appearance and because of the abundance of fuel. In early times the fire was placed in the centre of the room, and there was a hole in the roof above to let out the smoke. Then came the first improvement of setting the fire against the wall, and of ornamenting the outlet with a turret and with louvre openings. After a time there was a further improvement of stone-screens over the fire to shut out the smoke; and in the fourteenth century the channel for the smoke was entirely enclosed; and thus were chimneys first designed. But for more than 200 years they were not generally used except in the houses of the wealthy; and even there the large fireplace, with its cramped seats within the chimney breast, and the high-back settle which acted as a screen to keep off the wind, were but imperfect methods of warming. As soon, however, as coal began to be used as the common fuel, attention was directed to the discharge of the offensive smoke from it, and the best means of economizing the heat. Then it was that the great improvements began to be effected in the construction of fire-places. The earliest of these were by Keslar of Frankfort (1614), Savot (1625), Glauber (1669), Delesme (1686), and the Cardinal de Polignac (1715). The last-named writer, under the name of M. Gauger, published the first philosophical treatise on the subject, and it contains the germs of almost every modern improvement. He showed the advantage of having the sides and back of the stove placed at such an angle as to reflect the radiant heat into the room; and he also recommended that the chimney should be contracted immediately over the fire, so as to prevent the too rapid ascent of the heated air. These suggestions were still further improved by Franklin (1774), and by Count Rumford (1796); and since then the chief improvements have been in the methods of supplying the fuel, as from below or at the sides of the fire, and in directing the current of air upon it or through it. These improvements are countless, but the rules to be deduced from them are—

1. That the fire-place should be in the situation which commands all parts of the room, and is as nearly as possible at equal distances from the confines of it; so that the radiant heat may be equally diffused.

2. It should be raised to about 10 inches from the floor, so that the feet may be warmed and the face not scorched.

3. The grate should have a large frontage, of a semicircular form.

4. The back and sides should be composed of bad conductors (as of fire-brick), so that the heat may be stored as well as steadily radiated.

5. The bars should be as small as possible, in order that the fire may burn clear, and the heat be freely radiated.

6. The aperture for carrying off the smoke should be narrowed to the minimum size, in order that the heat may be retained, and the fire made to burn steadily.

7. The chimney should be as perpendicular as possible beyond the gathering.

8. The coverings or sides of the grate should be placed obliquely at an angle of 45° to the front, and they should be well polished.

9. The distribution of warm air into the apartment should be promoted by air chambers around the grate and flues, and the supply of air to the grate should be under the floor, as in the contrivances of Mr Boyd.

With all these arrangements, however, there is a great loss of heat, and there are many strong objections to the open fire-place. Thus:

The waste of fuel and of heat is enormous, for at least seven-eighths of the heat of the fire passes up the chimney, and is lost (Dr Arnott). Count Rumford estimated it at fourteen-fifteenths. Then, again, there is a very unequal effect in the distribution of the heat. Those who are near to the fire are too warm, and those who are away from it are not warmed at all; the law of radiation being, that the effects are inversely as the squares of the distances.

Another objection is, that the fire causes an uncomfortable draught along the floor of the room, and does not ventilate those parts which are above the level of the chimney breast.

And, lastly, there is a great deal of dirt and smoke, and there is danger of fire.

With all these disadvantages, however, our national habits have confirmed us in the choice of an open fire.

The close stove is used where fuel is scarce, or where the open fire is not admissible. It is a very ancient mode of warming, and is still commonly practised on the Continent.

The several varieties of stoves are,—Those which warm the air of the room by simple contact with the heated surface of the stove; those which supply a continuous current of hot air into the room; and those which deliver the warm products of combustion into the apartment. Of all these, the two former alone deserve consideration; for the latter are dangerous and unwholesome. Of the first, the simplest is the Dutch stove, which consists of an iron chamber in which the fuel is burnt. The stove is raised a little above the floor, and the products of combustion are carried off by a flue. In France, Germany, Sweden, and Russia, the stove is made of brick-tiles or porcelain. The fire-place is small, but there is a curious disposition of the flue, and this makes the stove a large and elegant structure. The materials, however, retain the heat for a long time, and therefore the stove requires but little attention, and is very economical.

When the warm products of combustion are conveyed into the room, as is the case with the common brazier, with Harper and Joyce's stoves, and with the various gas furnaces which have lately been contrived, there is great danger to health; for not only is the atmosphere made dry and hot, but it contains the poisonous products of combustion, which have on several occasions been fatal; in fact, the objections to most of the close stoves, whether they throw the products into the room or not, are, that they burn or overheat the atmosphere, and make it dry and uncomfortable. Besides which, they do not generally permit of a very complete renovation of the air, but merely cause a continual circulation of it within the room. To guard against these objections, the stove should be constructed so as to deliver the products of combustion entirely out of the room, and it should not be composed of materials that will soon become hot. The fire should never be so intense as to scorch the air, for that will produce a sensation of dryness and oppression. The supply of fresh air should be continuous, and the vitiated atmosphere should be removed by special contrivances at a higher level. A proper degree of humidity should be given to the air by means of evaporating vessels or wet surfaces, and there should be perfect and easy control over all the arrangements. When this is the case, the close stove has advantages over the open fire, in the circumstance of its being more economical and more uniform in its action.

A system of flues for hot air has been a common mode of warming among the wealthy from very early times. The Roman hypocaustum was but a set of flues running beneath the flooring, and conveying the smoke and hot air from a furnace outside the room. Exactly the same kind of arrangement is the ancient kang of the Chinese; and the modern invention of Mr Beaumont is also an example of it. Judging from the effects of these stoves, and the economy with which they may be maintained, they appear to have many advantages; but they require especial attention, and are not always under control; besides which, there is danger of the soot firing in the flues, and so becoming unmanageable; and, above all, they cannot be made the means of constant ventilation.

A closed pipe conveying steam or hot water is a modern invention. The effects are much more genial than those produced by a higher temperature, but the apparatus is expensive, and in the case of steam it requires constant attention; nevertheless, it is used with advantage in large public buildings, as in hospitals, prisons, barracks, &c.

The hot-water apparatus, in its simplest form (Kewley's), is on the principle of a siphon. It consists of a long pipe coiled about in the rooms to be heated, and having two legs of unequal length passing down into an open kitchen boiler; the short leg dips just under the surface of the water, and the long leg passes to the bottom of the boiler. As the water becomes hot, it rises in the short leg and circulates to the coils in the upper level, where it parts with its heat, and then descends in the long leg to the boiler. The apparatus is not adapted for any great height (not above 14 feet), and the water cannot be heated above 180° because of the tendency to a vacuum.

The second form of the apparatus is that contrived by the Marquis de Chabannes. It consists of a closed boiler, with the two legs of the siphon communica- ting with a cistern at a high level. These are filled with water, and when the fire heats the contents of the boiler, the hot water rises at once to the cistern, whence it is distributed by coils to the rooms to be heated, and then it descends to the boiler. By this arrangement the temperature may be raised to $212^\circ$, and the water conveyed to any distance.

The third and only other form of the apparatus is the invention of Mr Perkins. It is a closed circuit of comparatively small pipes filled with water. About one-eleventh part of the whole tube is coiled in a suitable manner, and placed in a furnace at the lowest level. From this a straight tube passes to the top of the building, and thence the pipe descends to the several rooms to be warmed, where it is coiled so as to expose a large radiating surface; from these it returns to the coil in the furnace. An expansion or safety tube is placed at the uppermost part of the apparatus, to guard against danger from the too great expansion of the heated water. The temperature of the water in the furnace coil may be raised to $400^\circ$, but the circulation and cooling in the return coils is so great that the water soon falls to $200^\circ$; in fact, when the return coils have a radiating surface about ten times as great as that of the furnace coil, it is hardly possible to maintain a temperature above $200^\circ$.

The quantity of heat given out by these contrivances is somewhat variable; but a cubic foot of steam at $212^\circ$ ought to give out enough heat to raise 130 cubic feet of air $10^\circ$, and a cubic foot of water will raise the temperature of about 300 cubic feet of air one degree for every degree of heat it loses. Tredgold, Hood, and others, have given the rules for ascertaining the length and surface-measurement of pipe which is necessary for heating given quantities of air, and have also determined the amounts of the different kinds of fuel which are required for the purpose; but this is not the place for the consideration of such facts.

**Artificial Illumination.**—In a sanitary point of view, this is a subject of great importance, for all the combustible bodies employed for the production of artificial light appropriate the oxygen of the air and form carbonic acid. They therefore vitiate the atmosphere to a large extent, and some of them also produce sulphurous acid, which by subsequent oxidation becomes sulphuric acid, and this exerts a corrosive action on metals and textile fabrics.

The principal illuminating agents are oil, tallow, stearic acid, spermaceti, wax, camphine, benzole, and coal-gas. The extent to which these several agents appropriate the atmospheric oxygen, evolve heat, and vitiate the air for the same amount of light, may be seen in the following table. The light evolved in each case is that of 26 sperm candles, each burning at the rate of 120 grains per hour; and the vitiating effect is calculated at the rate of 3 parts of carbonic acid in 1000 of air.

| Illuminating Agent | Consumption of each Burner or Candle per hour | Number of Burners or Candles required | Heating Power Calculated of Air raised 10 Degrees | Quantity of Oxygen consumed in cubic feet | Quantity of Carbonic Acid produced in cubic feet | Quantity of Air vitiated and consumed per cubic feet | |--------------------|---------------------------------------------|-------------------------------------|-------------------------------------------------|------------------------------------------|-------------------------------------------------|-------------------------------------------------| | Cannel gas | 35 cub. ft. | 2 | 22,500 | 7-92 | 3-91 | 1307 | | Benzole | 285 grs. | 5 | 19,340 | 7-35 | 5-89 | 1970 | | Camphine | 376 " | 4 | 20,630 | 8-37 | 6-02 | 2016 | | Common coal-gas | 250 " | 2 | 32,400 | 12-87 | 6-40 | 2146 | | Sperm-oil in Argand| 696 grs. | 3 | 31,250 | 10-10 | 7-10 | 2371 | | Oil | 756 " | 3 | 27,150 | 11-08 | 7-60 | 2569 | | Sperm-candles, 6 to the lb.| 136 " | 23 | 37,500 | 16-29 | 11-49 | 3811 | | Oil in a common lamp| 133 " | 27 | 43,600 | 17-62 | 12-39 | 4142 | | Wax candles, 6 to the lb.| 168 " | 21 | 40,800 | 17-91 | 12-60 | 4212 | | Stearic acid, do. | 140 " | 26 | 44,100 | 18-00 | 12-92 | 4318 | | Yellow moulds, do. | 143 " | 30 | 44,200 | 21-05 | 15-27 | 5108 |

From this it will be seen that, for the same amount of light obtained, the heating and vitiating effects of tallow candles are nearly four times as great as those of cannel gas; but then gas is not consumed economically; for the light is placed at a great altitude, and more gas is therefore burnt than is necessary to produce the required amount of illumination. This it is which has created so great a prejudice against gas, and which has caused it to be consumed in a wasteful manner, so as to heat and vitiate the atmosphere to a serious extent. In every case, however, it is manifest that the products of combustion should be discharged from the room, and that there should be a large supply of atmospheric air to provide for the heating effects of the illuminating agent.

The difference in the illuminating power and the vitiating effects of the same body (sperm-oil for example) is dependent on the way in which it is burnt, and it shows how necessary it is that combustion should always be maintained at the fullest point; indeed, the differences in the vitiating effects of the several fatty bodies are caused, not so much by differences of chemical composition, as by the vigour with which the combustion is maintained. It is therefore advisable that the supply of air to the combustible should be such as to maintain it in the most active state of combustion. This is the object of glass chimneys, of the various contrivances named oxydaters, of the thin and plaited wicks of candles, and of the expanded or sheet-like flames of gas. When the combustion is very feeble, a number of acid compounds are produced which are very offensive. The fatty bodies, for example, when burnt with a smouldering wick, or a large snuff, produce acrolein, empyreumatic vapour, and irritating fatty acids; coal-gas, when slowly burning, produces aldehyde, formic acid, &c.; and the half-burnt vapours of turpentine and benzole are equally offensive.

Coal-gas is a very complex mixture; it consists of about 40 per cent. of hydrogen, nearly the same quantity of light carbonated hydrogen, from 5 to 10 per cent. of condensible hydro-carbons, with variable proportions of carbonic oxide, carbonic acid, bisulphuret of carbon, nitrogen, ammonia, and sometimes traces of sulphuretted hydrogen. Many of these gases are poisonous; and therefore it is that coal-gas exerts an injurious action on the animal economy. If it is inhaled in a concentrated state, it quickly produces insensibility, which is followed by coma and death. An atmosphere containing from 7 to 12 per cent. of coal-gas will kill small animals in a very short time; and this proportion acting on man, causes headache and nausea, with great depression of the vital powers.

A mixture of gas and atmospheric air is explosive; and it would seem from experiment that the greatest danger is when there is 1 part of common gas to from 6 to 7 of air, or 1 part of cannel gas to about 10 of air. The force of the explosion under these circumstances is equal to that of about 30 atmospheres. These circumstances call for especial care in the use of gas, and in many continental cities there are authorized rules for the management of it. In Hamburg, for example, the gas-fitters are obliged to perform their work in an appointed manner. They must use tubes of wrought iron, or of brass, or copper; and in cases where these are not easily adapted, tubes of drawn tin must be employed. The joining must be made in a durable and solid way, either by means of sockets ground in and cemented with iron cement, or by screwing up, or by soldering. Any other kind of connection is forbidden. The tubes must be placed in localities where they are accessible, so that in case of leakage the mischief may be easily repaired. The cock must be constructed so as to make only a fourth part of a turn, and they must be fixed so as not to be removable from the tubes. All the pipes of one inch or more in diameter must be provided with stop-cocks, so as to shut off the gas in case of fire; and no one is permitted to use or alter the fittings without having them tested by means of a pressure of 1 inch of mercury or 14 inches of water. All the gas-fitters are sworn to adhere to these instructions; and in case of any damage from negligence, compensation can be claimed from the gas-fitter in a civil court of justice.

The sulphur which is contained in coal-gas is objectionable, because of its forming sulphurous acid, which soon absorbs oxygen from the air, and becomes sulphuric acid. This exerts a corrosive action on all kinds of textile fabrics, and has caused much mischief in libraries and warehouses; in fact, the amount of sulphur in 100 cubic feet of coal-gas is sufficient to produce from 30 to 50 grains of sulphuric acid. It is proper, therefore, to guard against the destructive effects of this acid by burning the gas in a closed chamber, so that the products of combustion may be carried entirely away; and there are many contrivances for accomplishing this.

A dangerous compound, called water-gas, has on several occasions been proposed for illuminating purposes. It consists of hydrogen, carbolic oxide, and carbonic acid, in various proportions; and to give it an illuminating power, it is naphthalized with benzole, or the volatile hydro-carbons of coal-tar. The gas is obtained by passing steam over ignited carbon, and the carbolic oxide which is so produced is a deadly poison; so much so, that the governments of France and Germany have interdicted its use.

There are two illuminating agents—namely, the oxy-hydrogen, or Drummond light, and the electric light—which do not vitiate the atmosphere; but they are so costly, and are so difficult to manage, that they are not used for domestic purposes.

Water Supply.—An abundant supply of wholesome water is one of the first essentials of health and comfort. Pure water cannot be obtained from natural sources; even that which distills from the earth, and falls as rain or snow, is charged with volatile matters which are often highly offensive; and the water which flows from the soil contains saline impurities which have been derived from the strata through which it has percolated. These are the earthy carbonates of lime and magnesia, the chlorides of the alkalies, the earthy and alkaline sulphates, with silica, alumina, organic matter, and frequently the nitrates of potash, soda, and lime. The proportions of these constituents vary with the nature of the soil through which the water has filtered; for example, the amount of carbonate of lime and magnesia may range from less than a grain per gallon to more than 20 grains, the former being the proportion in the water from the shallow sands of the tertiary strata, and the latter in the water from the chalk formation. So also with respect to sulphate of lime: in most of the streams of England, and in the water-bearing strata, the proportion does not exceed 5 grains per gallon; but in the hard selenitic waters of the London clay the proportion is from 20 to 30 grains. The existence of nitrates in water is generally a sign of putrid contamination. All the shallow wells of our large towns and cities are charged to a considerable extent with this salt, the acid of which is produced by the oxidation of organic matters which have drained from the sewers, and cesspools, and graveyards, and from the soakage of surface filth. While the soil is capable of producing this salutary kind of oxidation, the danger is kept in abeyance; but no one can say when this power may cease or be overtaxed, and then the danger is imminent. Water which has flowed from well-manured land is charged in the same way with alkaline nitrates; and that which has drained from a soil covered with peat, or has stood upon decaying vegetable matter, as the water of ponds and marshes, is commonly impregnated with organic compounds to a serious extent. As a rule, it is found that the water from the surface of the soil is not wholesome unless it has been collected in a sandy district which is not in cultivation. Those from the upper sands of the tertiary strata are generally excessively hard, from the presence of sulphate of lime. Those from the lowermost sands of that strata, as the deep well waters of London, are free from this impurity, and are frequently alkaline, from the presence of carbonate of soda. The water from the upper and middle layers of chalk is characterised by the existence of much carbonate of lime; and that from the upper greensands which lie upon the gault is not much charged with calcareous salts, but contains a rather large proportion of alkaline nitrates, with traces of phosphates. In the summer-time such water is soon covered with Confera and Diatomacea, which feed upon the nitro-phosphates, and form a thick scum upon its surface. The water from the sands below the gault is commonly the purest of all; but even this is occasionally impregnated with sulphate of iron that has been produced by the oxidation of iron pyrites. River waters have generally lost a great portion of their calcareous matter, from the escape of carbonic acid. A water which contains about 20 grains of saline matter in the gallon, of which about 12 or 13 are carbonate of lime, from 2 to 3 sulphate of lime, from 2 to 3 common salt, and with not more than 2 grains of organic matter, is generally well suited for domestic purposes. If it contain a larger proportion of carbonate of lime, it is unpleasantly hard, and causes a waste of soap, besides depositing a crust upon the interior of the vessels in which it is boiled. Every grain of carbonate of lime that remains in solution in the water destroys about 10 grains of soap; and therefore a calcareous water is wasteful for domestic purposes. When the calcareous salt is in the form of sulphate of lime, it is still more objectionable, because this salt is not precipitated from the water by boiling or by the addition of an alkali. The hardness is therefore said to be permanent, in contradistinction of the fugitive hardness of a carbonated salt. Such water not only destroys soap to the extent of about 7½ times the weight of the sulphate contained in it, but it is unfit for vegetable infusions, and for extracting albuminous matters. There are occasions, however, when this is desirable, as in the brewing of pale ales, when the object is to extract the saccharine matter of the malt, without much of the colour or the albumen. The water of Burton-upon-Trent, for example, which is so celebrated for the production of pale ale, contains about 28 grains of sulphate of lime in the gallon.

In consequence of the objections which have been raised to the hardness of calcareous waters, several processes have been suggested for the purpose of softening them. None of these processes, however, are applicable to the selenitic waters, which derive their hardness from sulphate of lime. In other cases they owe their action to the removal of the carbonic acid which holds the carbonate of lime in solution. Exposure to the air in a running stream, or boiling the water for a few minutes, or the addition of caustic lime, which is Dr Clark's process, will have this effect, and then the carbonate of lime is thrown down as a white insoluble powder. The latter process, which was suggested by Dr Clark in 1841, is generally thought to be the most effectual, but it has not yet been practised with success; for there is much difficulty in removing the precipitate from the water, and the suspended lime is apt to form concretions in the service-pipes. The quantity of lime which is necessary for the purpose will depend upon the hardness of the water; but it rarely exceeds 10 grains per gallon, and with this proportion the hardness of a chalk water may be reduced from 19 or 20 degrees to 6 or 7.

A water which contains but little carbonate or sulphate of lime, although soft and agreeable for domestic purposes, is apt to be dangerous, from its action on the lead of the cisterns or service-pipes. Experiments have shown that pure distilled water rapidly corrodes lead, and so does rain and snow water, and the water which has fallen upon sandy districts, and has not received much mineral impregnation. The corrosion of the lead, which is due to the combined influence of water and atmospheric oxygen, leads to the formation of the white hydrated oxide of the metal; and this, by combining with carbonic acid, becomes a hydrated carbonate. Part of this is thrown down as a white precipitate; part of it is also suspended in the water, and gives it a milky appearance; and a still smaller part, amounting to about 7 grains in the gallon in the case of the hydrated oxide, and 1½ grain in the gallon with the hydrated carbonate, are dissolved. These proportions of lead are quite sufficient to give to the water a poisonous action; indeed, as little as 1 grain of oxide of lead in 7 gallons of water has been known to act injuriously (Herepath); and 1 grain in the gallon has often produced lead-poisoning. The proportion which is thought to be harmless is 1 grain of lead in 20 gallons of water (Smith); and when it rises to about 1 grain in 10 gallons, it is approaching a dangerous quantity.

The facts which have been made out in respect of the action of water on lead are these:—That water which contains less than 2 grains of saline matter in the gallon cannot be safely stored in lead vessels or distributed through lead pipes. That a proportion of 6 grains of saline matter (chiefly carbonate and sulphate) may be distributed through lead pipes, but cannot be stored in lead vessels; and that when the proportion of sulphates and carbonates amounts to from 10 to 20 grains per gallon, the water is not affected by the lead to any appreciable extent. These facts show that there is danger in seeking for a too pure supply, or in softening the water to a very great extent.

Again, the presence of nitrates or chlorides, or an excess of carbonic acid, will also cause an injurious action on lead; and so will the falling in of leaves or dirt into a lead cistern, or the joining of iron pipes to the lead. The former in their decay produce a vegetable acid which dissolves the lead, and the latter sets up galvanic action, which corrodes it. Cases of lead-poisoning have occurred where lead pipes have been joined to iron ones; and it has sometimes happened, that although the water which flows through the pipe is wholesome, that which has stood in it for some hours is poisonous. This explains the fact, that in a large household the domestics who make their morning tea of the water which has stood in the pipes all night, will show symptoms of lead-poisoning, while the rest of the family are free from them.

In seeking for a supply of water, therefore, it is necessary to guard, on the one hand, against the existence of too large a quantity of saline matter, and on the other, to avoid that degree of softness or purity which will lead to an injurious action on the lead of the cistern or service-pipe. Water which contains nitrate or chloride in excess or solid vegetable matter, should always be rejected.

The mode of supply is likewise a matter of importance. Whenever it is practicable, the water should be conveyed to the storing places in covered channels, so as to prevent as far as possible the contamination of the water with filth. The reservoirs should also be covered; and the water should remain in them a sufficient time to deposit the grosser impurities. It should then be filtered through sand-beds into the reservoirs from which it is supplied to the public. As to the question of an intermittent or constant supply, there are many arguments of great weight which bear upon both sides of it. The advantages of a constant supply are, that the necessity for large cisterns, and the consequent exposure of the water to fouling, is greatly diminished; the water comes to the house cool and well aerated; and it is always ready for use. The disadvantages are, that the necessity for cisterns cannot be entirely obviated; that there is a great waste of water in the continuous flow of it; that it is delivered at so slow a rate that there is a needless loss of time in collecting it; that it cannot be supplied at a high pressure; that the pipes are apt to freeze; that when repairs are going on there is a total shutting off of the supply; and that the continuous flow is never sufficient to clean the drains or to flush the sewers. Besides which, in almost every case where the constant supply has been generally used, there have been practical difficulties, chiefly on the score of excessive waste, which have interfered with its continual action. The truth is, that in the houses of the wealthy and the careful it is a matter of little or no importance whether the supply is constant or intermittent; for, with proper attention to the state of the cistern, the supply is always sufficient and unpolluted; but in the dwellings of the poor, where the receptacle for the water is generally an open butt, receiving all the chance filth which may drop into it, and becoming tainted with the disgusting exhalations from the neighbouring closet, to say nothing of the insufficient capacity of the receptacle, it is a matter of serious moment whether there cannot be a perpetual flow. At any rate, there is some better system required than that which prevails in all the crowded localities of our great cities, where it is hard for the poor to obtain even that modicum of water which is required for their physiological wants, and where it is vain to expect from them those habits of cleanliness which are necessary for health, and for their social advancement.

As to the quantity of supply, it is manifest that it should be sufficient not only for the domestic wants of a population, but also for the purposes of trade and luxury. In the city of London it amounts to nearly 25 gallons per head per day; and in the cities and towns of Glasgow, Aberdeen, Nottingham, Preston, Oldham, Liverpool, Paisley, and some other places which are regarded as models in this respect, the daily supply is from 15 to 20 gallons per head. Looking, therefore, at the requirements of a population, and at the practical facts which have been ascertained concerning them, it may be concluded that a supply of from 12 to 16 gallons per head is required for purely domestic purposes, and that an addition of from 5 to 8 gallons per head is required for the purposes of trade and general cleanliness. This makes a total daily supply of 20 gallons per head; and this may be regarded as sufficient for domestic wants, for public baths and wash-houses, for the flushing of sewers, for the cleansing and watering of streets, for the extinction of fires, and for the supply of trades and manufactures.

The chief conditions of a water supply are:—

That the water should be of such purity and quality as to be fit for domestic purposes, without, on the one hand, being wasteful on the score of hardness, and on the other dangerous from its softness.

That it should be conveyed from its source in covered channels. That it should be stored in reservoirs that will permit of sedimentation, and be filtered through fine sand.

That the daily supply should not be less than 20 gallons per head of the population.

That it should be supplied at high pressure, so as to reach the uppermost storeys of the houses.

That the cisterns of every house should be constructed of harmless and durable materials; that they should be covered so as to exclude dirt and other impurities; and that they should have a capacity of at least 12 gallons per head, or 24 gallons per room.

That every closet should have a distinct supply, so as to guard against offensive impregnation.

That every court should have a separate stand-cook that may be used for flushing and cleansing.

That there should be a street supply sufficient for the accidents and emergencies of fire.

And lastly, that there should be a proper distribution for street fountains, for public urinals, and for the flushing and cleansing of sewers.

Cleaning, Draining, and Sewering.—In providing for the sanitary wants of a community, it is not sufficient merely to procure and distribute an adequate supply of good and wholesome water, but means must be taken for the removal of that water after it has become foul in the services of life and industry. Provision must also be made for the drainage of the soil, and for the quick disposal of all the refuse matters which are apt to accumulate in every large city. The cleansing of the streets, and the removal of common refuse, are usually provided for in every town and hamlet, and are generally enforced with the utmost care and regularity; but the drainage of the soil, and the disposal of sewage and liquid waste, have yet to be dealt with, so as to be inoffensive and technically useful. This is a problem which has hitherto baffled the science of the chemist and the skill of the engineer; and the experience of the past, as well as the lamentable errors of the present, have left it doubtful whether the old system of cesspools, with the appliances of modern science, would not have been preferable to the wasteful and dangerous methods of modern sewerage; for the fact is dawning upon us, that every river in the country is being fouled by the reckless discharge into it of matters which are due to the soil. Not that we can go back to the careless habits of our forefathers, when every house incorporated its own stink, and stood upon an oozing cesspool; but it is a question of serious importance, whether, if as much attention and engineering skill had been bestowed upon the improvement of that system, and the perfection of the cesspool arrangements, a more profitable result would not have been obtained than the present; for, however great may appear to be the improvement of the public health through the adoption of the modern system of sewerage, we must not forget that the experiment is only in the first stage of its development, and that we have yet to learn what will be the ultimate effect of the pollution of every watercourse in the kingdom.

Judging from the facts which are before us, it appears evident that the surface and subsoil drainage of every town and city should be altogether distinct from the sewers and cesspools, and that while the drainage may be safely discharged into the nearest stream, the sewage of the population must be dealt with in an independent manner. That which must be provided for is the collection and disposal of about 40 ounces of excrementations matter daily for each member of the community. Of this from 2 to 2½ ounces are dry solid, and with the present arrangements it is mixed with from 20 to 25 gallons of water, and is thus rendered unfit for every useful purpose; in fact, the matters contained in the public sewers consist not only of the solid and liquid ejecta of the population, but also of the fluid refuse of every branch of industry. They are composed of the special filth of kitchens, laundries, and dye-houses; the drainage of stables, slaughter-houses, and the public markets; the various liquid impurities of trade and manufacture; the washings of streets and alleys; and the whole water supply of the district. Each of these constituents has an influence on the composition of the general mass of sewage, and on the putrefaction to which it is subject. Analysis shows that the sewage of large towns contains from 15 to 80 grains per gallon of suspended matter, and from 35 to 76 of dissolved. Of the former about 35 per cent. is organic, and of the latter about 28 per cent. The mineral constituents are chiefly carbonate of lime and common salt, with small proportions of alkaline sulphate and earthy phosphate, together with the insoluble debris of the roads and the detritus of wheels and horse-shoes. The organic matter consists of the remains of vegetable and animal fibre, with a soluble extractive in a high state of decomposition. None of these can be utilized; and the organic constituents give off such an abundance of foul gases that they are a constant source of annoyance. The gases consist of about 73 per cent. of light carburetted hydrogen, 16 per cent. of carbonic acid, 10 of nitrogen, and traces of sulphuretted hydrogen, ammonia, and a putrid organic vapour that is in the highest degree offensive. Every gallon of sewage will discharge from 1½ to 1½ cubic inch of the gas every hour, and the fermentation continues for weeks. The effect of this in the atmosphere of the sewer is extremely dangerous, for wheresoever it escapes, like the emanations from cesspools and privies, it causes disease; in fact, it lowers the vital powers, produces nausea or actual sickness, and in length sets up a putrid form of fever which is exceedingly fatal. To prevent the escape of these gases the openings from the drains and gullies are trapped, and every effort is made to prevent the diffusion of the fetid gases into the houses and public way. But still the sewers must be ventilated; and to accomplish this, openings are left in the middle of the streets, out of which the gases pass without hindrance. It has been tried to ventilate the sewers by means of the rain-water pipes, or by tubes to the tops of the houses; but the foul gases diffuse themselves into the upper windows, and are offensive. It has also been proposed that the sewers should be ventilated by the street lamps, or by the church towers; but the only practical means of disposing of the gases is by the aid of charcoal placed in the course of the outlet channels. The efforts made to destroy the gases by means of furnace fires placed in special ventilating shafts have not been successful, partly because of the difficulty of effecting any large amount of ventilation in this manner, and partly because of the enormous expense which it involves.

Attempts have been made to diminish these evils by the use of small drainage pipes, instead of the large brick sewers which are commonly employed. It has been thought that, with a good arrangement of such pipes, the sewage would be quickly discharged, and would not have time to undergo the decomposition to which it is subject in the larger channels; that foul gases would not therefore be evolved from it; and that it could be more easily utilized than the putrid liquid matters of the common sewers. But these expectations have not been realized. In the towns of Croydon, Rugby, Tottenham, Uxbridge, and elsewhere, the system has failed; and experience has shown that it is not only an expensive system, but it is also a dangerous one, because of the mischief occasioned by the escape of foul gases when by accident a stoppage occurs in any of the pipes; for as there are no special contrivances for the outlet of the gases, they are forced through the traps and openings into the houses, and are thus a cause of annoyance and disease. Experience has also shown that the solid excreta which is thus collected cannot be utilized. with profit, and that the liquid refuse is as offensive, and is as difficult to dispose of, as the worst kinds of ordinary sewage.

That much has yet to be accomplished in respect of this matter, there can be no doubt; and in the meantime the objects to be kept in view are—

The construction of special drains for the discharge of the surface and subsoil drainage, and for disposal of the less offensive sallage from the domestic use of the water supply.

The formation of special drains and receptacles for the removal of the animal excreta.

The construction of the sewage-channels and the cess-pools of impervious materials.

The occlusion, by means of traps, &c., of the sewer-gases from the houses and public way; and the providing of distinct ventilating channels with deodorizing trays of powdered charcoal.

The existence of proper regulations for cleansing the public way, and for removing the house refuse.

And the adoption of some profitable and inoffensive means of utilizing the sewage and waste products.

Offensive or Injurious Trades.—All pursuits and occupations have their influence on the health of those who are engaged in them; even the luxurious habits of the wealthy affect the condition of the body, and mark the evils of a too artificial state of existence. But this is not the place to discuss the special effects or particular maladies of each occupation, but rather to lay down such general rules for the management of offensive trades as may be applicable to the purposes of hygiene. And, in the first place, there are certain manufacturing processes which ought not to be conducted within the confines of a city; for they are either dangerous on account of the poisonous matters they discharge into the air or soil, or they are insufferably offensive. To the first of these belong the trades and occupations that deal with corrupting organic matter, and which poison the atmosphere with the products of putrid decomposition; among these are slaughterers and knackers, bone-boilers and catgut-spinners, tanners, and the makers of artificial manure. Nearly akin to these are the different processes of manufacturing chemists, as the making of mineral acids, the assaying and dissolving of metals, the roasting and smelting of ores, the preparing of lead and arsenical pigments, the distilling of crude pyroligous acid, and the treatment of the various products of gas-making, as coal-tar and ammoniacal liquor. To the second belong the trades of tallow-melting, soap-boiling, tripe-dressing, gas-making, varnish-making, bleaching, &c., &c.; but in all cases, whether the offensive operations are conducted within the confines of a town or not, it is proper that every care should be taken to prevent the escape of offensive effluvia; and this is necessary, not merely because of the nuisance occasioned by it, but also because of the fact that every particle of matter escaping from the domain of art is a loss to the manufacturer. Every effort should therefore be made to collect the volatile and waste products, so that they may be hereafter utilized; and if it so happens that the volatile product is not of sufficient value to pay for the cost of its collection, it should be destroyed or rendered innocuous by some special contrivance, as by conveying it through a flue into the furnace fire. In this manner the disgusting fumes from melting tallow, from boiling bones, or tripe, or whalebone, and from the making of varnishes, manures, and other such like offensive operations, may be consumed and rendered harmless.

Again, when it is necessary to collect or store materials that are apt to undergo decomposition, they should be placed in air-tight receptacles and treated with disinfectants; and when the storage of such materials is large, the chamber containing them should be ventilated by a faner, and the offensive effluvia conveyed into a furnace fire. All liquid products of a volatile or noxious character should be transported in casks or close barges, and should be stored in air-tight tanks. Nor should there be a larger stock of such materials than is necessary for the immediate requirements of trade.

And lastly, in every establishment where liquid organic substances are likely to soak into the soil and be offensive, the pavement should be impervious, and it should be laid upon a proper incline, so that the waste liquors may run off and be collected in a covered tank, or discharged into a public sewer. All the sinks and gullies should be effectively trapped, and there should be an abundant supply of water to ensure the needful cleansing. In addition to which, the business of the factory should be under such regulations as will prevent unnecessary annoyance.

There are some trades which are so dangerous and unwholesome as to require particular care on the part of the operatives. This is so in the manufacture of lead and arsenical pigments, in the making of lucifer-matches, and in the dry grinding of steel, &c. All these demand especial precautions. The buildings should be well ventilated; the operations should be conducted in a cleanly manner; there should be no waste of the dangerous products; the working clothes should not be worn out of the factory, and they should be frequently cleansed. Those who work in lead should drink a lemonade acidulated with sulphuric acid, and the lucifer-makers should use an alkaline beverage. Under all circumstances, the action of the dangerous matter should be checked as much as possible by cleanliness, by proper prophylactics, and by effective ventilation.

The discharge of opaque smoke into the atmosphere is nearly always a wasteful nuisance; for the evidence of those who are best able to judge of the matter is to the effect that it may be easily prevented, and that it ought not to be allowed. The mischief of it is, that it obscures the atmosphere, interferes with domestic cleanliness, begrimes the architecture of a city, and causes the inhabitants to shut out the air which is necessary to ventilation. The remedy is a little attention to the manner of supplying the fuel to the fire, or the employment of one of the countless contrivances which have lately been invented for the consumption of smoke.

The Burial of the Dead.—This has been a subject of sanitary regulation from the earliest times. The ceremonials of the Jews and ancient Egyptians, the processes of embalming which were practised by the Egyptians and Peruvians, and the burning of the dead by the Greeks, the Romans, and the Ethiopians, were but the means of preventing danger from putrefaction. And even in later times, when the Romans practised interment in the soil, it was performed in an allotted space beyond the walls of the city. Gradually, however, the custom of burying the dead within cities, and even within the temples of religion, was adopted, and at last it was learned how dangerous the practice was. As far back as the sixth century the mischief of it was anticipated, and edict after edict was promulgated by the church against it, but with little or no effect until the legislative enactments of different countries put a final check upon it. In France, Germany, America, and, lastly, in the metropolis of this country, the practice of intramural interment has been prohibited, but not until it was shown that the emanations from the dead were a fruitful source of danger to the living. It is a serious matter, that close beneath the feet of those who attend the services of the church, and all around the sacred edifice, there are heaps of human remains undergoing putrefactive decay, and evolving foul gases which are known to be a cause of disease. Instances are not rare where these gases have suddenly gushed forth, and have killed with the energy of a thunder-stroke; and often have they spread a pestilence that has decimated the neighbouring population. All this, with the knowledge that the gaseous emanations of animal corruption are among the most deadly poisons with which we are acquainted, has led to the condemnation of intramural interment.

The questions which present themselves in respect of this matter are,—the situation of the place where the dead should be buried; the character of the soil which is best suited for the promotion of animal decay; the space which should be allotted for each interment; and the time which should elapse before a grave is disturbed. Add to these the treatment of the body before it is interred, and the manner of dealing with the present churchyards and overcrowded vaults.

The situation of a public cemetery is not an unimportant question; for it involves considerations of economy, of convenience, of reverence for the dead, as well as care for the living. It should be accessible by easy carriage-roads; and better still if it can also be approached by a railway; for this secures economy in the transport of the coffin and mourners, and does away with that worst of all necessities, the conveyance of the dead in cabs and other public vehicles. If the site be upon the side of a hill,—a situation which is always in harmony with the feelings of the sorrowful, and encourages that reverence for the dead to which all consideration is due,—it should be carefully ascertained that the drainage of the soil is not downwards into localities where the water is used for domestic purposes. The proximity to a well-wooded district, and a situation which will permit of complete isolation from dwellings, are always to be preferred.

The character of the soil which experience has proved is best suited for animal decay is a light porous soil, which will permit of atmospheric diffusion. A stratum of wet clay is most objectionable, and a peaty soil will have the effect of preserving the body for an indefinite time.

The graves should never be so close as to prevent the free access of air through the porous soil to the body, and the earth should never be saturated with that unctuous corruption which is characteristic of the overcharged graveyards of the metropolis. It must not be forgotten that the object of interment is to effect the complete decay of the body; and every facility should be offered for this purpose. The rich and the poor are nowise different when they meet in the grave, and both should be subject to the same regulations, for both are liable to the same changes in death, and have to pass through the same processes of decay, in order that the elements of their bodies may be restored to the living world, and may circulate in accordance with the law and economy of nature. We may endeavour to gratify our selfish feelings, and try to keep together the frail fabric of the cherished dead; we may swathe it in ceremonies, confine it in metal, or wood, or stone, and build it into vaults, and heap pyramids upon it; but all is in vain: the law of nature is, that it shall decay, and its elements pass again into the living world, and so circulate for ever. Our efforts, therefore, should be to expedite the processes of nature, and not to check them. There should be no burying in metal and building into vaults, but all our dead should find a common resting-place in the soil.

The superficial space which should be allotted to each grave should not be less than 20 feet. The largest coffin is about 6 feet long and 2 feet wide; and if such coffins, with a superficial area of 12 feet, were packed side by side, without earth between them, as many as 3620 could be disposed of in an acre; but such an arrangement would be manifestly improper, and therefore it has been decided that a sufficient layer of earth should be placed between the coffins, to enable the physical and chemical powers of the soil to perform their appointed duties. What the space for a coffin should be, is still a matter of uncertainty. It varies in different countries, from a superficial area of 30 to 90 feet.

The former will permit of 1452 graves in an acre, the latter of 484. In the resolutions which were issued from the Home Office, in accordance with the Burials Acts of from the 15th to the 19th of the present reign, it is ordered that the grave spaces for the burial of persons above 12 years of age shall be at least 9 feet by 4, and those for the burial of children under 12 years of age, 6 feet by 3. The former (36 square feet) will permit of 1210 burials in an acre; and the latter (18 square feet) 2420; the average of both being 27 square feet for each grave, or 1815 burials to the acre; but as the number of children buried is generally twice as great as that of adults, it would give an average of 24 square feet for each grave, or 2017 graves to an acre. Mr Chadwick says that the well-considered regulations for burials in towns give about 1452 common graves per acre. From all of which it may be concluded that a superficial space of about 30 square feet should be allotted to each grave. And it is also necessary that space should be allowed for the gravel walks in a cemetery, and for the ornamental culture of trees; for nothing is so salutary as the growth of vegetation in the organic soil of a burial-ground.

Another regulation from the Home Office is, that not less than 4 feet of earth shall be placed over the coffin, or rather that the coffin shall not be within 4 feet of the ordinary level of the ground, unless it contains the body of a child under 12 years of age, when it shall not be less than 3 feet below the level.

Lastly, it is recommended that only one body shall be buried in a grave at one time, unless the bodies be those of members of the same family; but although this regulation is a very salutary one, it is not observed in any cemetery or burial-ground in England, except in the burial-places belonging to the Jews, amongst whom the custom has prevailed from an early date.

The practice of burying the dead in vaults or catacombs or brick graves is fundamentally wrong, but still it prevails to a large extent in this and other countries; and the regulations which have been made in respect of it are, that the coffin shall be of lead, and that it shall be entombed in an air-tight manner in stone or brick-work, with proper cement. The space which is allotted to them is generally 9 feet by 5, or rather 9 feet by 4 and 9 feet by 6 alternately, and sometimes there is a channel along the head of the vault for ventilation. The notions which prevail in respect of the protective power of lead coffins and brick vaults are very erroneous. If the coffins are made so tight as to prevent the gradual escape of the pent-up gases, they will sooner or later explode; but commonly the lead is purposely left with small fissures and holes for the outlet of the gases. A time also comes when the outer wood coffin decays, and then the weight of the lead and its superincumbent tier of coffins flattens the metal case, and the organic remains are squeezed out, or are crushed by the heavy pressure. The lead also corrodes and becomes converted into white lead, by which means the coffins are pierced with myriads of small holes. These changes may be seen in almost every church vault in the kingdom, and they illustrate the absurdity and danger of such a mode of burial.

As to the time which should elapse before a grave is disturbed for a new tenant, it will vary with the character of the soil, the distance of the body from the surface, and the number of coffins in the grave. In a good soil, and under favourable circumstances, an adult coffin with its contents will have disappeared in 8 or 10 years; whereas in a clay or peaty soil it will remain for a century. It is generally assumed, that in a moderately good soil a period of 14 years is sufficient for the decay of an adult; that for young persons between the ages of 5 and 16 a period of 10 years is sufficient; and for infants under 5 years about half the time. But long before this the soft parts of the body will have decomposed, and the skeleton alone will remain. This, however, at last decays, and crumbles into dust, which blends with the neighbouring soil. Not until this has taken place can it be said that the grave is ready for another tenant; for the return of dust to dust, and the total dissolution of the body, is alike required for the purposes of hygiene and for the respect which is due to piety and affection.

The delay which occurs in the burial of the dead has often suggested the necessity for providing some means for the preservation or custody of the body before interment, so as to prevent the mischief which is too often occasioned by putrefaction. In the houses of the poor this is especially needful, for it commonly happens that the dead are kept in the rooms which are occupied by the living; and many days may elapse before the necessary arrangements can be made for the burial; during the whole of this time, the occupants of the room are exposed to the fetid emanations from the putrid and sometimes infectious body. To guard against this, it has been proposed that there should be houses of reception for the dead, where the corpse might be detained in decent and respectful custody until the appointed time for its burial. These houses might also be used for the reception of bodies found dead in the public way; and means might be taken to prevent putrefaction until the period for interment. Provision has been made for this in most of the local sanitary acts, but it has not yet been put into practice, partly because of a fear that it would violate the feelings and domestic affections of the poor, and partly because it might be abused by those who are too eager to get rid of their dead; for if the body were once deposited in the reception-house, the further cost of its removal and interment might fall upon the local authorities. Altogether, the subject is beset with difficulties, but it is clearly one that requires consideration, for it might be developed so as to be of great advantage to the community.

The treatment of the existing evils which arise out of the present overcrowded state of the church vaults and graveyards is a matter of some importance. In the city of London, where this state of things has called for a remedy, it has been found that the most effectual way of dealing with the mischief is the following:—After a sanitary inspection by the government officer, an order in Council is issued for the final closing of the vaults. This is done under the supervision of the sanitary officer for the district; the coffins are arranged in order, and filled with dry earth. They are covered to the depth of from 18 inches to 2 feet, with the same sort of earth; and over this is laid a stratum of coarsely-powdered vegetable charcoal to the depth of 3 or 4 inches. A ventilator or two should be carried from the vaults to the top of the church, and the ventilator need only be a pipe of about 4 inches in diameter. The vaults are then built in, and permanently closed with brick-work. In the case of the graveyards, they are levelled and covered with a stratum of fresh earth, in which trees and shrubs are planted, and the whole is neatly laid out with grass. Vegetation acts as a salutary agent by absorbing the liquid humours from the soil, and by appropriating the organic vapours which may escape from the ground.

Disinfectants and Antiseptics.—It may not be out of place to refer in a very general way to the operation of these agents, and to their value as disinfectants; for putrefaction in one form or another is the chief cause of the unhealthiness of towns.

There are two classes of these correctives,—namely, those which check putrefaction by giving stability to the organic compound, and those which appropriate or absorb the fetid products. The first of these are properly called antiseptics or antiputrescents, and the second deodorizers or disinfectants. The antiseptics are common salt, vinegar, sugar, alcohol, creosote, the empyreumatic oils of wood or peat or coal, and the metallic salts, as chloride of zinc, corrosive sublimate, sulphate of copper, muriate of iron, alum, &c. None of these agents entirely prevent putrefaction; they merely check it by combining with the animal matter, and forming compounds which are not prone to decay. They are employed in many operations of the arts, and in some cases are the popular means of preserving food.

The deodorizers act in one of two ways,—they either absorb and fix the fetid gases, or they utterly destroy them. Those which operate in the first way are the volatile acids, as vinegar, sulphurous acid, nitrous acid, and spirit of salts; the mineral compounds, as the salts of lead, iron, zinc, and manganese, all of which latter unite with ammonia and sulphuretted hydrogen, which are two of the most offensive constituents of almost every putrid vapour. Those which act in the second way are chlorine, hypochlorous acid, the manganates and permanganates of the alkalies, powdered charcoal, and fresh earth. The modus operandi of these is nearly always alike; they give oxygen to the putrid matter, and so destroy it. Where it is necessary to act upon organic vapours and putrid masses, the volatile disinfectants, as chlorine or hypochlorous acid, should be employed; but where the putrid substance is in a solid or liquid form, the other agents may be used: of these, the manganate or permanganate of soda or potash (Condy's fluid) is the most rapid and safe; chloride of lime is also effective, and so is charcoal or dry earth, both of which absorb the foul gases, and bring them into chemical contact with atmospheric oxygen. Both of these agents therefore require free access of air. Practically, it will be found that Condy's fluid acts most freely on liquid products; it disinfects sewage, putrid water, and foul sores, almost immediately; solid substances, as animal remains, and the semifluid matter of cesspools, are best treated with a layer of charcoal or dry earth. A good deodorizer for the preservation of dead bodies during the time which elapses before burial can take place, is sawdust charged with a solution of sulphate of zinc and dried; it may be scented with a little camphor, to take off the cadaverous smell. Game also may be packed in it, when it is to be sent to a distance; and animal matters generally are well preserved by it. None of these agents, however, are applicable to the deodorization of sewage on a large scale, because of their cost. It has been calculated that the cheapest of them (chloride of lime), even when used in the proportions of only twelve grains per gallon, would cost nearly L:240,000 per annum to deodorize the sewage of London. Quicklime, therefore, is generally employed in these cases; but it is not a perfect deodorizer, for it merely absorbs the sulphuretted hydrogen of the putrid compound, and casts down a part of the organic matter which is in solution; but if the precipitate is not quickly removed from the supernatant fluid, it passes into a state of decomposition, which is not less offensive than the original sewage. At Leicester and Tottenham, this process is used on a rather large scale, and with some success in a sanitary point of view, but with none in a commercial.

Fire is a powerful and complete disinfectant: it is there used in many processes of the arts where offensive vapours are evolved.

There are many other practical questions which the limits of this article will not embrace, as the economy and adulteration of food, the purity of medicines, the action of poisons and antidotes, the specific and general causes of endemic diseases, the origin and spread of epidemics, the importance of quarantine, &c.; but the facts which have been discussed will illustrate the leading principles of hygiene, and will suggest the rules which should be adopted for the protection of life and the preservation of health.