70
246. As. I have before stated, no inferences are deducible from the record*
of barometric pressure. As regards temperature and moisture, it is scarcely-
possible to estimate the direct effect of these, conditions apart from their ac-
tiQii on surrounding circumstances of soil and water-supply. We find, how-
ever, that cholera first manifests, itself when the hot weather has fairly set
in; that some of the most violent out-bursts of the disease, as at Soonwarra,
liana, and Dunwahi (paras. 82,103,126), occurred during a period in which the
mean daily temperature ranged from 90° to 95°, the wind blowing with a mean
velocity of ½ miles per hour ; a difference between the dry and wet bulb of
the hygrometer, ranging from 28° at 10 a. m. to 36 o at 4 p. m., at the same
time indicating a dryness of atmostphere which can scarcely be surpassed.
When the description of the sites of the villages alluded to above is borne in
mind, I think it must be conceded that neither extreme heat or extreme dry-
ness of the atmosphere checks the development of cholera. It may here be
noted also, that under these atmospheric conditions cholera was conveyed from
Lucknadown to Soonwara, a distance of fifteen miles, and from Jubbulpore to
Dunwahi, twenty-seven miles. It is the opinion of the natives that cholera is
most severe in the hot weather, but continues longer in the rains.
247. But while there are numerous facts recorded in the report that
strongly support the opinion that the choleraic influence is diffused solely by
means of human intercourse, there are, on the other hand, many instances in
which the arrival in a town or village of persons suffering from cholera was not
followed by an out-break of the disease among the population; and in the returns
from all the circles a considerable number of villages appear, from which one or
two deaths only was reported. A reference to Table VI. and to the map also
will show that the proportion of villages attacked varied greatly in different
parts of the epidemic area, and that, in all, the greater proportion of the villages
escaped. Moreover, frequent instances are given of villages in close juxta-posi-
tion, where one suffered severely from cholera, while the others experienced com-
plete immunity.
248. It is evident then that all localities, or the populations inhabiting
them, are not alike amenable to the effects of the choleraic influence; and we have
to consider what information the report affords regarding the conditions that
favour the manifestation of the disease. The epidemic prevailed with the
greatest severity in the districts of Seonee, Jubbulpore, and a portion of Mun-
dla ; these districts extend over a hilly and undulating country, having an eleva-
tion above the sea varying from 1,300 to 2,300 feet; in parts covered with dense
forest, in parts open and treeless, having a remarkable variety of soils and sub-
strata, and intersected in all parts by rivers and streams, which far the most part
have a rapid fall, and which almost everywhere effect a rapid drainage of the sub-
soil water. Referring again to Table VI. and to the map we find that the
highest rate of mortality occurred in the trap formation; that the disease also
visited with great seventy villages along the banks of the Nerbudda, the Hirun,
and the Pureyat rivers, that traverse the wide alluvial tract of the Jubbulpore
district; and that, on the other hand, the proportionate number of villages attacked,
and the ratio of mortality, were comparatively low in the metamorphic tracts of
Kuttunghee, in the Seonee district, and the tracts of the same formations and of the
sandstones that are found in the district of Jubbulpore.
249. The conditions of site, soil, sub-strata, and water-supply that surround
the towns and villages in these various situations differ considerably. In the
trap formation the villages are situated on the tops of rocky ridges, or on high open
plateaus; they are almost invariably built on hard impermeable rock, bare of soil,
and where sub-soil water is non-existant ; in fact, more dry, healthy sites could
scarcely be found anywhere.