the original poison, was the cause of the symptoms? He (Dr. Richardson) was inclined to the latter view, and gave some experimental evidence in support of his position. He admits, at the same time, that further experiment was required, and argues that, until this point was defined, no sound progress could be made in the study of epidemics.

It is impossible, in an abstract, to give more than the briefest outline of a communication written in so condensed a style, and opening up for consideration so many subjects, each differing in detail, yet having but one object. But the final propositions laid before the Society are as follows: That, by experi ment, it might be ascertained:

1. In what excreta the poisons of certain epidemic diseases are located. 2. By what surfaces of the body such poisons may be absorbed, so as to produce their specific effects.

3. Whether the virus of a disease, in reproducing its disease in a healthy body, acts in the development of the phenomena by which the disease is typified, primarily or secondarily; i. e., by its own reproduction and presence, or by the evolution of another and different principle or product.

4. Whether climate, season, and other external influences, modify the course of epidemics, by producing modifications of the epidemic poisons, or modifications in the system of persons exposed to the poisons.

ART. 2.-On the Study of Epidemic Diseases, illustrated by the Pestilences of London. By Dr. GREENHOW.

(Lancet, Nov. 28, 1857.)

In this paper, which was read before the Epidemiological Society, Nov. 2, 1857, Dr. Greenhow begins by stating that it is but an imperfect knowledge of any epidemic disease that can be acquired from its study, however careful, in a single visitation, or even in a succession of visitations in the same place. Perhaps even the study of a single form of epidemic disease would leave many points obscure which might be rendered clear by its comparison with other diseases of the same class. In the study of an epidemic visitation, it is further necessary to investigate the condition of the public health anterior to the outbreak, and to note whether this at once returns to its usual state afterwards. Many cosmical phenomena, the state of the weather, peculiarities of seasons, and other evident circumstances, will also deserve notice. Hence, likewise, it will be useful to inquire into the influence, if any, which these several circumstances have produced upon the lower forms of organized beings, and particularly upon domestic animals and cultivated vegetables. Epidemic diseases have varied greatly in type and character from century to century, and this very clearly not because they have been excluded by means of restrictive precautions, but because of some change unfavorable to their development in the crasis of the people, or in the conditions amidst which they exist. To these peculiarities, therefore, the student of epidemiological science must likewise direct his attention. Nor must the attention be exclusively devoted to these positive phenomena; many negative facts will also demand investigation. Thus the singular immunity from surrounding pestilence occasionally enjoyed by the inhabitants of particular districts, by particular races, or by particular classes of persons, well deserves consideration. Let us now proceed to illustrate these suggestions by a reference to the epidemics of London. These are evidently divisible into two classes, viz:

1. Epidemics apparently depending upon some purely atmospheric influence, and which comprise the single form of febrile disorder so well known under the name of influenza.

2. Epidemic pestilences depending also in a great measure upon atmospheric influences, but requiring likewise some definite condition of persons or places, peculiar to each form, for their full development. Under this head will be included the black death, sweating sickness, plague, dysentery or alvine flux, and cholera, also a form of alvine flux. These epidemics have all been remarkable for their irregularly-periodical character and their successive appearance, each having been almost exclusively predominant for a certain time.

In studying the history of these pestilences, it is observable that they have all possessed certain common characters. Each has been attended by some peculiarity of season; and the prevalence of fog, haze, or mist, during the visitation, has been recorded in regard to most of them. Not the least important point in the history of London pestilences is the absence of pestilence during the eighteenth century and its reappearance in the nineteenth century; and this, notwithstanding a general improvement in the public health. The general death-rate of London, which is now 25 in the 1000, exceeded 35 in the 1000 a century since. It is not less interesting and remarkable that pestilence has now reappeared in exactly the same form in which it took leave of our forefathers, about the close of the seventeenth century. The cholera of our times, which has now, on three separate occasions, carried off some thousands of the inhabitants of London, is identical with the dysenteria incruenta of Willis, and the diarrhea colliquativa of Morton, which, on many occasions, carried off in the autumns of the last quarter of the seventeenth century as many people from the then population of the metropolis as would be represented by the deaths of 11,000 or 12,000 persons in the present London. On one or two occasions, the deaths were so numerous as to be only duly represented by those of 18,000 or 20,000 persons in the present day.

It will be interesting here to pause for a brief space, and contrast the mortality caused by former pestilences with that produced by cholera in our own times. The means of accurately estimating the mortality caused by the black death and sweating sickness, do not exist; but there are reliable data from which the mortality of plague may be computed so as at least to approximate to truth. The plague visitation of 1625 raised the mortality of London for that year to more than five times the average amount; and the visitation of 1636 raised it to two-and-a-half times the death-loss of the ordinary healthy years of that period. Supposing the cholera visitations of 1849 and 1854 to have been equally fatal to the inhabitants of London, the deaths, which were 68,755 in 1849, and 73,697 in 1854, would have been 266,885 for the earlier, and 133,442 for the later outbreak. The total mortality of the last great plague year, that which immediately preceded the great fire, was little short of 100,000, whereof nearly 70,000 died of the pestilence. The general death-rate of London is now 25 in the 1000. The general death-rate of London in that calamitous year was 253 in 1000-that is, fully one fourth of the inhabitants were numbered with the dead. The plague death-rate (included in the general death-rate) was 178 in each thousand of the living. This was, however, very unequally distributed, the mortality being fearfully high, even when compared with this to us dreadful mortality, in some districts, and in others comparatively low. Sixty thousand deaths occurred in nine weeks. In the week ending September 19th, upwards of 8000 persons perished: 3000 of them in one night, which was probably the most fatal night that ever occurred in London. The cholera death-rates of our own day, alarming as they were at the time, sink into insignificance when contrasted with these death-losses of the seventeenth century. They are even insignificant when compared with the average death-rate of analogous disease at the close of that great epidemic epoch. The average annual death-rate of cholera, diarrhoea, and dysentery, for the ten years 1846-55, including the last two visitations of cholera, and all the years in which diarrhoea was most fatal, was 257 in the 100,000 persons. For the ten years, 1681-90, when the deaths from this class of diseases had already begun to decrease, the average annual death-rate from analogous diseases, was 477 in the 100,000 persons.

The apparently sudden outbreak of epidemic diseases is one of their commonest attributes, and has been often quoted as an argument in favor of their importation. This suddenness is, however, only apparent; for, with few exceptions, epidemic outbreaks have been preceded by sufficient indications of the existence of an epidemic constitution, tending towards, and more or less gradually passing into, the form of the approaching disease. Plague was preceded by pestilential fever, into which it again passed at its decline; and the visitation of cholera in 1832 was preceded by a distinct, although small, increase in the fatality from analogous affections in London. Forty-eight deaths from cholera morbus were recorded in the London bill of mortality for 1831, although the epidemic

form of cholera did not show itself until the early part of 1832. Thus it would appear that the magazine was ready prepared here, even if the spark which fired it came from abroad. Probably all the forms of pestilence to which the author has referred have been only malignant forms of diseases constantly present in London. Plague was not absent from London for twenty-five years anterior to the great fire. It even occasioned a very considerable mortality on many occasions that are not usually spoken of as pestilential periods. So likewise in our day do deaths from cholera, indistinguishable from epidemic cholera excepting for its less rapid course, annually occur, although, like plague, it only appears in its epidemic and pestilential character and more distant intervals. On this point, however, the author guards himself from misapprehension. He does not deny the importation of cholera any more than he denies the contagiousness of plague. The question must still be viewed as an unsettled one, requiring much careful inquiry for its elucidation.

The chief conclusion deducible from the facts here put together is, that of the several forms of epidemic disease which have at different periods visited London, influenza has maintained its precise character from century to century, because it is independent of the extrinsic condition of the population it attacks. Black death, sweating sickness, plague, and cholera, whether in the seventeenth or nineteenth century, have appeared in succession, and then disappeared because they have required for their development some definite but temporary condition, either of the human subject or of his place of abode. They have in turn appeared, and they have in succession departed from London, not because they have, at the one time, been,imported with bales of cotton or by means of the sick, or, at the other, been effectually excluded by repressive precautions; but because at the one period the organic matter out of which plague or cholera is brewed abounded, and at the other period has been wanting. The exciter may, perhaps, have sometimes come to us over-sea, but it would have failed to light up the epidemic had it not here met with materials upon which it could

react.

ART. 3.-On the injurious Effects of Under-Ground Kitchens. By Dr. FREDERICK J. BROWN, of Chatham.

(Sanitary Review, April, 1858.)

The darkness and damp inseparable from under-ground apartments, and the exhaustion occasioned to those who occupy such apartments by the frequent ascent and descent of stairs, are the reasons which Dr. Brown urges for using the basement-story for cellar-purposes simply, and not for kitchens.

"The servant-girls of London exemplify remarkably well these evil effects of damp; also the injurious results of deprivation of the solar rays. Their etiolated condition, and their breathlessness, show the anæmia (the impoverished state of blood) under which they suffer; and the functions peculiar to women are carried on imperfectly, or are absolutely suspended; hence the headache, the pains in the side, the palpitation, and the dropsical ankles, so frequently witnessed in this class. These circumstances are well known to the profession, and are especially familiar to those members who practise in the metropolis. Organic disease of the heart is originated by these causes in some instances.

The unhealthiness of under-ground tenements is shown by the statistics of the city of Liverpool; the subterranean inhabitants being in a much worse sanitary condition than the supraterranean population.

"Thus, then, the effects of darkness are disease, and not merely delicacy of structure; and the morbid condition is aggravated by the damp that is associated with the darkness.

"The next consideration is the exhaustion attendant upon the frequent ascent and descent of stairs. The necessity of answering the front door, and of ascending to the upper part of the house in the performance of domestic duties, obliges the servant to undergo much fatigue in running up and down stairs. The carrying of a burden up stairs is attended by a very much greater expenditure of strength than is the case in carrying it along a level. Girls that are breathless, owing to their anæmic condition, and oftentimes dropsical about the ankles,

cannot afford the increased exertion that the circumstances necessitate; it is torture to them.

"The value of land in London causes houses to rise vertically rather than to increase in dimensions horizontally. The same reason, namely, high value of land, is slowly but surely operating on the style of building in country towns. It will inevitably, if persisted in, bring about an approximation in the death-standard between the towns of small size and the great urban populations of this country.

"It is the duty of physicians to point out the evil effects of subterranean apartments, and to impress upon the minds of builders, and upon the public generally, the injurious consequences of damp, dark kitchens, so placed that a multiplicity of stairs must be used in the performance of daily domestic duties.

"In provincial towns, the wives of artisans and others of the working classes, occupying houses with basement kitchens, suffer much from exhaustion due to the necessity of frequently ascending the stairs. A woman gets up from her confinement pale and weak, from want of generous living, and perhaps, also, blanched by hemorrhage; she is obliged to go up and down stairs some score of times in the day, and the consequence is a prolonged convalescence, with palpitation and other distressing symptoms, and sometimes even displacement of organs such as the womb.

"Besides these ill effects upon women, the children are apt to meet with accidental falls down the stairs, and to harass their mothers by the watching necessary to prevent such accidents. Darkness and damp produce unfavorable effects upon growing children; and scrofula, and rickets, and consumption, and swelled bellies, are the result.

"In the name, then, of humanity, let a stop be put to this sepulture of human beings, and to this treadmill exercise of women rendered weak and blanched by their premature interment."

ART. 4.-On the Influence of Sewer Emanations. By Dr. HERBERt Barker.

(Sanitary Review, April, 1858.)

Dr. Herbert Barker has lately been making some inquiries as to the influence on the health of animals, of exposure for a long time to air rendered impure by the diffusion through it of emanations from sewers. The full details of these experiments are recorded in the essay "On Malaria," written for the Fothergillian Prize of the Medical Society of London for 1858; but, as the subject has important sanitary bearings, Dr. Barker has published in the "Sanitary Review" an outline of his researches.

The gaseous emanations from sewers have been subjected, to a certain extent, to chemical analysis. There have been thus detected in them sulphuretted hydrogen gas, sulphide of ammonium, carbonic acid, nitrogen, sometimes sulphuretted hydrogen, and various organic living products. Dr. Odling has recently pointed out the diffusion of an alkaline gas through sewer air.

For the purpose of experiment, Dr. Barker selected a large cesspool, which received, together with the animal excreta, the liquid refuse of an inhabited house. The cesspool was full, and had at all times so bad a smell, that during hot weather the vicinity was scarcely tolerable. The inhabitants of the house, however, had not for many years suffered from any epidemic; nor did the near presence of the sewer seem to affect their general health.

Dr. Barker had built, close by and nearly over the sewer, a small room. Two gutta-percha tubes, one inch in diameter, were carried down into the cesspool through its upper wall, and terminated in two large inverted funnels a few inches above the surface of the sewage matter. The other ends of the guttapercha tubes were in the small room, and were so constructed that they could be opened or closed at pleasure. By a bellows attached to the free end of one or other of the tubes, he was enabled at any time to draw off the sewer air and subject it to examination. He did this on numerous occasions-at times when the weather was very hot and the neighborhood of the sewer most offensiveat times when the temperature was very low and the place inodorous. As a

general rule, the sewer gas yielded neither acid nor alkaline reaction, but sometimes the reaction was alkaline. At all times, mixed with the common air, carbonic acid gas, sulphuretted hydrogen, or sulphide of ammonium, were detectable. When the reaction was alkaline, ammonia was evidenced. He could detect no other foreign products in the sewer air. He tested for evidence of

cyanogen compounds, without any affirmative indication.

When this inquiry had progressed for several weeks, he tried the influence of sewer air on animals exposed to it for a long time. For this purpose, he had made a chamber of wood and glass, with a cubic measurement of 5832 cubic inches. One of the gutta-percha tubes was introduced into it at the lower part; from the upper part he carried a tube in the form of a small chimney. At the point were the long tube piping from the chamber made a right angle upwards, it expanded into a conical box, in which a lamp was placed, so as to create when alight a constant upward draught. The whole played well. When the chamber was closed and the lamp arranged, a current of the sewer air was kept steadily passing through it. Dr. Barker also attached a pair of bellows to the chamber, in such a way that he could at any time remove the air by working them, and subject it to investigation, without interfering either with the experiment which might be progressing. In the experiments to be related, the animals operated on were placed in the chamber, were fed by a funnel whenever necessary, and were subjected to the sewer gases as is now to be described.

EXPERIMENT 1.-Dr. Barker placed a young dog in the box at twelve o'clock noon, and kept a current of the cesspool air passing constantly through the chamber by means of the chimney draught. Half an hour after the exposure, he became very uneasy and restless; he vomited, and had a distinct rigor. In the course of the day he suffered from diarrhoea and tenesmus. After twelve hours' exposure, he was allowed fresh air; but on the next day, when he was removed altogether, he was exhausted. The diarrhoea and vomiting had ceased, but he refused food for some hours. However, he soon recovered.

The air breathed in the chamber by this animal yielded evidence of sulphuretted hydrogen.

EXPERIMENT 2.-On placing another dog in the box connected with the cesspool, and subjecting him to a free current of the foul air, similar results occurred. In ten minutes the creature became very uneasy, and soon afterwards suffered from vomiting and diarrhoea. After these effects, however, he suffered but very little, although kept in the chamber for five hours. After removal he quickly recovered.

EXPERIMENT 3.-A mouse placed in a cage was let down into the cesspool, to within three inches of the surface of the contained soil. The cesspool was freely open above, so that there was no exclusion of air. The animal was also well plied with food. After this exposure for four days, the animal seemed lively and well, and took his food heartily. On the next day he was found dead.

EXPERIMENT 4.-Another dog was subjected to the cesspool air during a period of twelve days, with such brief intermissions only as sufficed for rapid cleansing of the box. Throughout the time food was liberally supplied him. The results were as follows:

During the first day the animal was restless and uneasy, and refused food. On the second day vomiting came on, and was repeated frequently during the day. In the afternoon there was diarrhoea, accompanied by thirst and rest lessness. On the third day, in the morning, he had marked shiverings, and refused all food. The feet were somewhat swollen. Towards evening he slept, but had a peculiar kind of tremor with each inspiration. On the fourth day he took food, and drank some milk. He slept during the forenoon, but was restless towards evening. On the fifth and sixth days he was much the same. On the seventh day he was restless and relaxed, and ate no food. On the eighth day he ate but little food, and was restlesss; he was by this time thinner and feeble. On the ninth day he had eaten no food for two days, and seemed very ill and miserable. He was therefore taken from the box while it was cleansed, and offered food, which he ate voraciously and to repletion. When removed