It is remarkable that in the evidence on this part of the subject received by the Cholera Committee, lowness of site is not very prominently set forth among the unfavourable sanitary conditions. It is, in fact, specifically mentioned only five times. This may be because a difference of level does not strike the attention so much as other points of difference, where one street is compared with another, or one house with another house; and in many instances it may certainly be inferred that the localities visited by Cholera had a low level as well as other features of insalubrity. At the same time it is evident that lowness of level was not more essential as a condition for the prevalence of Cholera in other, smaller places described by the correspondents of the Committee than it was in the metropolis. In Swansea, as Mr. Michael's Report shows, the disease prevailed much more severely in the higher part than in the lower part of the town. In Maidstone, Dr. Plomley remarks,—“ There were in no street more than two deaths, and in no house more than one death, except in the upper part of Stone Street, the most elevated and the most remote from the river, yet the very worst in its sanitary condition." In Southampton, again, Dr. Oke records that, "Cholera broke out with fearful violence in Charlotte Place, an assemblage of houses in a high situation to the north end of the town, and detached from it; the streets here being wholly formed of small pauper tenements, narrow and dirty, the front built with more respectable houses, but the whole without sewers. And with regard to Leeds, Dr. Castle states that "the disease was least prevalent by the water-side, and most so on the higher ground."

In these instances, where the epidemic fell with such violence upon the more elevated parts of provincial towns, there were found to be present, as in similar instances in London, many of those conditions which are commonly associated with the prevalence of epidemic disease. But it is important that an exaggerated and incorrect view should not be entertained with regard to the relation subsisting between

even these conditions of insalubrity and the spread of Cholera in towns. It is undoubtedly true that Cholera rarely prevailed with great intensity except in badly-drained and foul spots, or in dirty and badly-ventilated houses, such as are inhabited by the poorest classes. But it is equally certain that in some public institutions, and even in some private houses, where, excepting, perhaps, the want of ventilation, the conditions of insalubrity did not exist in a marked degree, the disease caused a large mortality in proportion to the number of persons exposed to its ravages; and further, that in the towns visited by it, some of the localities which presented the worst features of insalubrity escaped altogether, or suffered in the slightest degree. Of the former fact, illustrations will be found, if needed, in the Appendix (Tables I. and II.), and reference will be made to it again in a subsequent part of this Report. Of the latter fact, the escape of parts of towns apparently adapted above most others for the reception of the epidemic, instance as striking, perhaps, as the following will occur to the recollection of every one who has watched the progress of Cholera in London, or any large town.

After describing the severe ravages of the disease in a part of Manchester called Gaythorn, Messrs. Leigh and Gardner* give the following as an instance of the seeming capriciousness of its course :

On the bank of the Medlock, and lying on the southeast of Gaythorn, but separated from the latter by the Manchester gas-works, some large manufactories, and a curve of the river, is the district called 'Little Ireland.' It is occupied almost entirely by the most squalid and indigent Irish immigrants; has numerous pigsties, undrained houses and cellars, a population crammed to suffocation; has the exhalations from the river rolled over it by an opposite high bank, and has long been known to be one of the most unhealthy localities, and in the worst sanitary condition of any in Manchester. In a straight line it is but a few hundred yards, scarcely more than three hundred, from Gaythorn, and

History of the Cholera in Manchester in 1849. London: 1850, p. 25.

yet a very few cases of Cholera only have occurred in this locality; indeed, but five cases, and four of these happened when the disease was generally declining."

Mr. Simon, in his "Second Annual Report on the Sanitary Condition of the City of London," makes a general statement to the same effect. "It is unquestionably true," he says, "that many habitual seats of fever were visited by Cholera; on the other hand, many of the worst fever-nests in the whole metropolis were unaffected by it;" and the late Dr. Taylor, in his "History of Epidemic Cholera in Huddersfield," observes that "One of the most remarkable singularities of the epidemic is this, that after attacking one, two, or three persons in a bad locality, it will cease there; again, it will altogether pass by other neighbouring spots, as bad or worse than the one visited. One house will be invaded, whilst others, much nearer to the nuisance supposed to be concerned in the production of the disease, will escape."

The foregoing facts have an important bearing on the theories of the epidemic, which may here be briefly noticed. The marked preference of Cholera for low unhealthy sites and crowded dirty dwellings, suggests at once the inference that the morbific cause, whatever its nature, finds the conditions for its increase or for its action, at least in part, in the impure atmosphere of such places. But in the application of that theory of Epidemic Cholera, which attributes it to a "general state of the atmosphere" or "atmospheric influence," brought into action by "localizing causes,” a difficulty is already met with. Such a cause would be expected to produce its effects wherever the "localizing conditions" exist. Yet it has been seen that very many places, some towns, and many smaller places and parts of towns, having these conditions, suffered but slightly or wholly escaped. And it is obvious that no supposed want of susceptibility of the disease in the individual inhabitants will explain the absence of the epidemic under such circumstances from entire towns and districts, or indeed from entire groups of the houses of the poor. If, therefore, the cause be one generally present

through the atmosphere, there must be some other condition. essential for its action besides the known conditions of insalubrity; and this unknown condition must, in some instances, have been absent throughout entire towns,-in others, only in limited spots.

The theory of a "Cholera matter" not equally diffused through the atmosphere, but only partly distributed and transported in some way or other to the places affected, is more easily reconcilable with the facts hitherto examined. The partial distribution of the epidemic, and its absence from some of the places which have the conditions obviously favourable to its development, would be well explained by this theory; and the occurrence of a very small number of cases of the disease in some places having the characters referred to, might be accounted for on the supposition that, although a small portion of the "Cholera matter" reached those places, its increase was prevented by accidental circumstances.

It may further be inferred from the foregoing facts, that if the cause of Cholera be a material poison, it has most probably not a gaseous form, since a gas soon becomes diffused through the air and dissipated, while the cause of Cholera remains many days producing its effects in one limited spot, -even in a part of one building: it must on that assumption be supposed rather to have the form of minute solid or liquid particles, which may become fixed by attaching themselves to the surfaces of other bodies.

Lastly, it may be observed that the close relation in which the intensity of the epidemic seems to stand to density of population and activity of traffic, though not inconsistent with any one theory, especially suggests the probability of the disease being in some way propagated by human intercourse.

III. A third character of an epidemic of Cholera is its long duration in a country, or even in a town of large size.

In England the disease persisted through the last three months of the year 1848, and the whole of the year 1849; and in the previous epidemic of 1831 and 1832, its duration

was equally protracted. In the individual cities and large. towns of England, it continued, in both visitations, uninterruptedly prevalent during several months; and in London itself was persistent through nearly the whole period of its presence in the country.

This character of Cholera distinguishes it from the Epidemic Influenza, the duration of which in one town does not extend beyond a few weeks, and in a whole country does not exceed two or three months; and it is a character which must not be neglected in an inquiry respecting the cause and mode of diffusion of the disease.

The atmosphere of a country, or of a town, is never completely at rest. Perpendicular currents take place in it, when it is not undergoing horizontal movement; and horizontal currents of great rapidity are frequent, and produce in given spots such considerable changes of temperature and of other meteorological conditions, as prove that the air has come from great distances. The very different qualities of the south-west wind and of the north-east wind, respectively, during the winter in London, are, for example, so marked as to leave no doubt that the one has passed over the northern part of the European continent, and the other over the Atlantic Ocean.

Now, marked changes of the atmosphere occurred during the prevalence of Cholera in London in the summer of 1849; and yet there were no corresponding interruptions to the continuance of the epidemic, or variations of its intensity. In illustration of this statement it is only necessary to refer to the annexed Table showing the changes of the wind during the months July, August, and September, as they were noted at Greenwich, and communicated to the RegistrarGeneral by Mr. Glaisher. Among the frequent changes in the direction of the atmospheric currents which took place during these three months, it may be noticed, for instance, that for eight days together, in the middle of July, the wind blew from the north-east and east at the average rate of 55 miles a day; for eleven days together from the south and