74
Seonee, Saugor and Mujhowlee, and the village of Moral ; and by a reference to
the Statement appended showing the mortality from cholera in the different dis-
tricts during the epidemic of the present year (1869), it will be seen that the
highest rate of mortality was reached in the districts of Kaepore and Belaspore,
where the people depend entirely on tanks or streams for water, and will riot use
wells, even if they are provided for them. A tank, however, may be a fairly
safe source of water-supply, if it does not receive the surface drainage of the
town or village near which it is situated, if it retains a depth of water not less
than 6 feet in the hot weather, if it is faced with masonry so that the water is
deep at the place where the people draw water, and if the practice of bathing
and washing clothes in it is not permitted. The Jooma talao at Nagpore is a
remarkable instance of this kind.
Tanks formed for irrigation where the villages near which they may be
situated are not dependent on them for water for domestic use, do not produce
greater liability to cholera.
262. The effect of rain-fall on the prevalence of cholera cannot be easily
shown in a tabular form, for, as it affects only a condition that influences the
manifestation of the disease, and probably has but little effect in the transmission
of the infecting matter from place to place, excepting in so far as it affects traffic
and intercourse, it cannot be shown how much the spread of the disease in a
locality in a particular period is due to the diffusion of the infecting matter, and
how much to the prevalence of the conditions under which alone it can take
effect. For instance, in Table IV. the sudden increase in the number of villages
attacked in the Sehora circle in the first ten clays of June is not due to the rain-
fall registered, but to the out-break of cholera at Gurchapa (para. 154) and the
consequent dispersion of the Bharatees assembled.
263. Again, rain would have very a different effect according to the water-
supply of the towns and villages exposed to infection ; its effect on a stream or
tank would depend greatly on the amount of the rain-fall in relation to the
degree of the surface pollution of their banks ; where the water is derived from
a surface well or from a well sunk in porous strata, the effect of rain would not
be visible for many days or until a considerable quantity had fallen. Examples
of the apparent effect of rain are shown in para. 106, and in the account given
of the prevalence of cholera in Nagpore city.
264. In Statement IV. the rain-fall is tabulated with the number of vil-
lages attacked in each week during the rise and decline of the epidemic of 1868.
In this year cholera had spread but little before rain fell ; but it would appear
that the heavy fall of rain registered at Jubbulpore early in June was followed
by an increase in the prevalence of cholera in the 2nd and 3rd ten days over the
trap formation of the neighbouring tracts of Burailla and Burgee, where the
water-supply is largely derived from surface wells ; on the other hand, in Shai-
poorah and Patun, where most of the villages attacked derived their supply from
rivers and streams, the progress of cholera was apparently checked by the same
fall of rain. Again, in the trap formation of Lucknadown, Keolaree, and Mundla,
cholera did not reach its maximum till after the heavy rain that fell over those
tracts of country in the middle of July, in Patun, on the other hand, cholera
reached its maximum of prevalence early in July, prior to which there had been
only slight showers, and subsided after the moderate fall of rain which then fell.
265. Statement VII., however, shows that the influence of rain on the
spread of cholera is comparatively slight and partial. In 1869, a season of
drought, when the country was more than usually parched, and where in some
places even forest trees withered, the prevalence of cholera in the greater num-
ber of the districts, over which it spread reached its maximum and had already