2
Medical Department, I have had a personal acquaintance with the main facts
of every cholera epidemic in Southern India from that date down to the present
time. From the year 1859 down to 1865, I have had to trust chiefly to the
Medical returns and reports of the Army, Jails, and Civil Dispensaries for the
evidence of the presence or absence of cholera in any locality, but from 1866
down to the present time the death registers of the whole population of twenty-
six millions have been available for the purpose of this inquiry.
Epidemic
cholera
does notarise spontane-
ously inSoutliernlndia-
3. From all that I can ascertain malignant or epidemic cholera is not
a natural product of Southern India. It is quite true that the
very earliest records we have of the disease describe it as
occasionally prevailing in Malabar, Arcot, Bellary, and on the
Coromandel Coast, and there can be no doubt that the whole of the peninsula, in
times past, was subjected to invasions of cholera from the north, as in the year
1818, the invasion of which year is so graphically described by Scott, and in
the more recent invasions to be presently recorded. But the fact of a disease
being met with commonly in a locality is no proof that it is of endemic origin.
When we come to examine into the life-history of cholera, as Dr. Bryden has
done, we shall find that no conditions of soil or climate in this part of India are
capable of perpetually renewing, what for want of a better term I shall desig-
nate, the contagium of the disease, and that, except in very rare instances, an
invading cholera never survives beyond four years, and in
most instances is extinct in a much briefer period. In this
respect cholera follows precisely the same law as small-pox,
and possibly also some other epidemic diseases.
Phenomena common
to cholera and other
epidemic diseases.
It chooses by preference to occupy new ground, that is, it finds the fittest
conditions for its growth among populations that have not recently been
ravaged by cholera. It is affected more or less by seasonal changes during the
natural course of its life ; active and deadly in its destructive powers at one
period of the year under peculiar meteorological or climatic conditions, and
dormant or inoperative at other periods, when a different order of meteorological
phenomena prevails. Like small-pox, too, after a season of unusual and wide-
spread devastation, it dies away completely, and is not renewed until a further
invasion from without occurs.
Tendency of cholera
to become extinct in
Southern India, de-
feated by periodical
new invasions from
Lower Bengal.
4. But although the evidence, as to the endemic character of a cholera
capable of epidemic development, in Southern India, is very
weak and dubious, there can be no doubt that some localities
do harbour and reproduce the contagium for a longer period
than others. There are certain districts in the Madras
Presidency in which a reproduction of an invading cholera
will go on for three, or even four, years, after the primary invasion, and there are
other places in which the reproduction either does not occur at all, or lasts
for one season only, leaving a long interval of two or three years of complete
rest between one invasion and the next following it.
In the districts in which cholera lingers for three or four years after the
invasion, we have been in the habit of supposing that the disease was a true endemic
of the soil ; but, although the conditions of soil and climate in such districts do
probably approach very nearly to the conditions of the natural habitat of cholera
in Lower Bengal, yet there are probably some points of difference as yet
unascertained. The history of the latter months of 1858 and 1868 show most