Although we believe it will be found as impossible to assign any satisfactory reason for the disease breaking out with such violence at that period and in that district, as to explain why Indian cholera has always been a more virulent disease than the European form of it, which used once to be epidemic among our ancestors, we may nevertheless pass in review some of the explanations which have been attempted of the apparent_change in the disease, or fresh outbreak of it, in 1817.

It has been a favourite French notion to throw the onus of the production of cholera in India on English domination, and to attribute it to neglect on the part of the English Government of the great canals and works of the Mahomedan emperors. This idea was broached before the Conference, but was entirely dissipated by our able English representatives. We need not inquire where those great works were situated, or at what period they fell into decay. It seems sufficient to remark, that cholera is first known to us in districts in which there never were such works, and that its great centre at present is in a part of India where none such ever existed.

At the time of the outbreak much importance was attached to food to bad rice and to decayed fish; but it was never shown that with respect to them there was any state of things in 1817 that had not often existed before in Lower Bengal. We know that bad food predisposes to many diseases, and that some kinds of it produce in Europe, as in India, attacks, and often fatal ones, most closely resembling cholera; but we have no reason to suppose that they generate epidemics. The state of the weather previously to the outbreak was investigated, and it seems to have been ascertained that the seasons had been very irregular, and that there had been extensive inundations ; but although it has been from the first very clear that cholera bears a distinct relation to the seasons, and that its diffusion is aided or impeded by meteorological changes, yet few have considered it probable that any such atmospheric irregularities as had been observed could have produced the great outbreak of 1817.

Then it has been said, and undoubtedly with truth, that increased intercourse helps the spread of cholera, and as the increased tendency to spread is almost the only fresh characteristic of the malady in 1817, it has been attempted to connect increased communication in India with that period. We know of no good grounds for this, except the assembly of the large army of the Marquis of Hastings in that year. But Lower Bengal, and more especially the portion of it where cholera showed itself first in 1817, is entirely out of the course of the

usual

usual movements of Indian armies-we have already seen that it is out of the direct course of pilgrims; and as to increased communication and travelling in India, the improvement in them has been a gradual process; and it appears to us to be a mere arbitrary assumption to assign the period of 1817 in particular as the date of its commencement. The first steamboat did not reach India till 1826, so it is a mistake to suppose, as some have done, that steam helped to convey cholera to the Persian Gulf, which it reached in 1821.

It seems on the whole very improbable, especially with reference to the history of other diseases, that we shall ever be able to ascertain why the very invading character of cholera, as the Conference terms it, should date from 1817.

When the members of the Conference go on to recommend a more careful study of the circumstances under which the disease occurs in India, they carry us entirely with them.

They observe, 'We do not know all the localities where the disease exists in its endemic state, nor the relations between its endemicity and epidemicity-this is a question of statistics.' On these questions undoubtedly a flood of light might be thrown by statistics, and already a good deal has been done in India in that direction. A registration of deaths in some of the principal stations, if carried out as already often pressed on the government of India, and as lately commenced in some, would, if coupled with accurate meteorological observations, have ere now furnished valuable results. Now that the whole odium of being cholera producers has been thrown on our Indian possessions, the least we can do is to strive to get thoroughly to the bottom of the question.

It seems highly probable that season is one of the greatest agents in the production of epidemicity; this apart from all theory as to how that complex cause operates. Thus the disease is believed to be endemic in the deltas of the Ganges and of the Mahanuddy, and in both the maximum prevalence of the disease is in the hot weather. This is true of Bombay also. Again, its minimum prevalence appears in these three districts to coincide with the maximum of the rainfall, although the regularity of the diffusion of cholera in Bombay seems to be interfered with by the introduction of fresh disease by pilgrims at particular

seasons.

In Calcutta the mortality within the town has sometimes been as high as 6500 in the year; in Bombay it has been as high as 4500. Yet there must be some great difference in the conditions under which the disease exists in the two places, when we find that the smallest number of deaths in Calcutta in the year has

never been less than 2500, while in Bombay it has dwindled. down at times as low as 145. Then as to our large military stations in Upper India, we know that the season of great epidemics has generally been after the first rains have fallen, after the extreme hot weather is past. In them cholera is scarcely known in the cold weather. In southern India again, and down towards Cape Comorin, we find that it is during such cold weather as they have in those parts, that cholera sets in; that it comes along with the cold north-east winds in the end of October and in November. Thus we ought to be able eventually to make something of the fact that it has its favourite seasons of prevalence in different parts of India. Surely these differences are capable of explanation.

Again, can we say in what places cholera is endemic? Do we know accurately whether it may be always found in the bazars of our military stations—for instance, in Dinapore, Benares, Allahabad, Meerut, Bellary, or Poonah? Why is it not yet fixed in Lahore and in the Punjab? At how many seats of pilgrimage is cholera endemic? Surely all these are questions that might be solved by a little continuous careful observation.

Then the Conference asks various very pertinent questions. 'Has every epidemic its root in an endemic? Is there such a thing since 1817 (they need not have limited themselves to this date) as cholera breaking out spontaneously where it is not endemic? Do pilgrims carry cholera with them to their festivals, or do they acquire it at the seat of pilgrimage?'

But the number of desiderata we could ourselves enumerate is very large :

Under what circumstances do soldiers get cholera in marching, and under what in barracks?

Why do European troops in garrison in Calcutta, where cholera is especially endemic, never encounter the frightful outbreaks known in other places?

As we know that the ill-fed and the ill-housed usually suffer most, why do the well-cared-for European soldiery suffer so intensely?

Why has the proportion of mortality to attacks increased among them of late years?

Is it beyond all question that troops in barracks attacked by cholera should always be moved into camp?

Is the greater frequency of cholera among Madras than among Bengal troops, marching in districts where cholera is not so fixed as in Bengal, to be explained solely by their larger number of followers and families, or is there any difference in their encamping grounds, or in their habits?

How

How far have railways, termed by the Conference the chief carriers of cholera,-after ships,-accelerated the propagation of the disease?

How far is cholera introduced into gaols, and do they become permanent sources of it?

Are the seeds of cholera beyond all doubt contained in the excretions? if so, how long may a locality or articles of dress remain contaminated by them?

What share in the causation of the disease is attributable to bad water?

Has the supply of good water to Bombay had a marked influence on the disease?

Have the violent epidemics of 1857 or 1861 in northern India coincided with unusual prevalence of the disease in Calcutta or in Bombay?

Are there cholera waves propagated every year from certain centres and reaching certain distances, as some have supposed?

There are many other questions of detail which we cannot here enter upon, but regarding which information is wanted. If it were once obtained and the results classified, many of the prevalent beliefs on such subjects would either be dispelled or be placed beyond all question; but such information cannot be acquired in a day. We are in hopes that some of these questions may have been worked out by a medical Conference, which we are glad to learn has been recently held at Simla.

Then meteorology must be studied in its largest acceptation; the action of heat and moisture, not only on the air, but on decaying animal and vegetable matter; its effect on soil, so far as it is permeable to air and moisture. And this brings us to another question well worthy of study.

Much attention has been paid to geological formation in Europe, and it has been all but certainly established that cholera prevails more on alluvial and tertiary than on primary formations, in low rather than on well-raised sites.

In India the disease occurs on the alluvial soil of the delta of the Ganges, on the kunkur, a peculiar limy concretion further up its banks; on laterite, on sandstone, on granite, on trap or its decomposed form, the black cotton soil; but long before 1817 it had shown a distinct preference for low-lying alluvial soils. In such cases it may be required to make allowance for a denser population and a probably less healthy race, as well as for the geological formation. But an accurate collection of facts on this head would be a valuable addition to what has been already done in Madras,

While discussing the subject of soil, the Conference perhaps carry their theoretical views a little too far, when they declare their opinion that it is not safe to disturb the earth or to take up pavements during the prevalence of cholera. They generally steer pretty clear of theory, but they have all but adopted Pettenkofer's views about soil and subsoil water. They enquire, Has every place where cholera breaks out got a state of soil and of subsoil-water such as must coincide, according to Pettenkofer's views, to produce an outbreak of the disease?' Given a

Pettenkofer's views may be summed up thus. cholera germ in the excretions of cholera patients, wanted a suitable soil for it to germinate in. A suitable soil is any porous one, with the subsoil water not very distant, with its upper layers porous enough to admit of the free entrance of air as the upper layers of it dry on the retiring of the subsoil-water. On such a soil cholera will develope itself, and chiefly when the subsoil-water begins to recede and the soil commences to dry up. He thinks that an unusual fall of rain or of snow, which increases the amount of the subsoil-water, is sure to be followed eventu ally by an increased development of the cholera germ. It is to variations in the height of the subsoil-water that he attaches most importance. He has worked out this theory in its application to Bavaria and to parts of Germany with wonderful ingenuity. He is confident that it will explain most of the phenomena of the occurrence of cholera according to season in India. But we doubt much whether his theory is one of general application. Even in Bengal the amount of cholera, as far as we know, bears no relation to the rainfall of the preceding season, although cholera usually diminishes much during the height of the rains, a phenomenon explained, according to him, by rain preventing the air from permeating the soil. Nevertheless in the middle of the rainy season, when there can be no fall of the level of the subsoil-water, cholera may suddenly break out, as it has often done at Bombay, and as it has done exceptionally in the neighbourhood of Calcutta. Cholera does not prevail there most, when the subsoil-water begins to sink from its highest level. In other parts of India epidemics occur before the rains are over, and they take place as readily on the top of a kunkur bank, when the subsoil-water may be sixty or seventy feet distant, as when the soil-water is only removed a few feet from the surface. And with the subsoil-water as deep as fifty feet, how can one suppose that its rise or fall of a few feet can affect the surface very materially? And how does cholera occur in mountainous places, where there is often no collection of subsoil-water at all? We believe that cholera may occur with the subsoil-water at

any