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with the greatest intensity in those tracts of country in which the water-supply
becomes most scanty in the hot weather, or where it is most commonly exposed
to the influence of the sun and rapid evaporation, that the epidemic would reach
its maximum when the temperature of the air was highest, and evaporation most
rapid ; and that it would generally decline 011 the advent of the monsoon, or even
as its approach was indicated by a change of wind, a lower temperature, in
creased moisture, and diminished evaporation. That such are the conditions that
accompany the rise and decline of cholera in these Provinces, is made evident
by the statistics given of the epidemics of the past two years, and the tables of
atmospheric conditions that accompany them.
270. In the hot weather of 1868 the water-supply of the country was more
plentiful than usual, and was not generally liable to the form of pollution above
described. The number of villages attacked by cholera before the rains was com-
paratively small ; several of the severest out-breaks, however, occurred at this time
in villages in which extreme scantiness of water-supply was the chief insanitary
condition. In 1869, a season of drought, by far the greater number of towns
and villages are attacked in the hottest weather, and when the water-supply is
lowest ; and the highest rate of mortality is attained in the districts of Raepore
and of Belaspore, where the water-supply is chiefly derived from shallow tanks or
pools freely exposed to the influence of the sun and rapid evaporation.
271. There is then reason to believe that when cholera occurs in the hot
and dry weather the development of the disease is often due to the use of water
rendered impure by the putrefaction of animal matter that has previously
existed in the water. In the rainy season it is no doubt more commonly due to
sewage matter conveyed into the drinking water by surface drainage or by per-
colation.
272. Regarding the relation between the use of impure water and the
development of cholera, there is no reason to believe that water impregnated
with impurities of the kind above described, is ordinarily the exciting agent in the
production of cholera, or the immediate cause of the disease.
273. It is, indeed, not improbable that the excreta of patients suffering
from the disease contain the infecting matter of cholera, and that the disease may
be sometimes directly communicated by such matter being introduced into the
drinking water ; but that cholera can be rapidly diffused over a wide area by such
means, is scarcely possible; it is altogether improbable that in the large number of
villages attacked during the dry weather of the present year choleraic excremental
matter can have been introduced into the water-supply ; and the pollution of
wells or other sources of supply by means of the vessels used in drawing water,
I believe to be an accident that very rarely occurs.
274. Many of the most severe out-breaks described in the report, as at
Rana, Soomvarra, and Dunwahi, occurred under circumstances which afford no
ground for suspicion that the water was subjected to such a form of pollution ;
and it may be observed that, in all the instances given in the report in which
severe cholera followed the arrival of persons from an infected locality, the water
had been obviously impure or had been subject to sources of pollution prior to
the communication of the contaoion.
275. In many instances in which the appearance of cholera had been pre-
ceded by the pollution of the water by dead bodies thrown into the river, the
disease did not break out in the population drinking the water until the arrival
of an infected person. Thus at Pindrae (para. 105) the population had for many
days been drinking the water of the Wyngunga, polluted with the bodies of the
persons that died at Soonwarra ; but cholera broke out among them only on the
arrival of a man from elsewhere suffering from the disease. °In the instance of