172

Report on Kála-ázar .

     We have seen then that the disease invaded, decimated
and died out of the Garo Hills just as it afterwards did in the
southern portions of Goalpara and Kamrup, and that it is
therefore not endemic there. The escape of Sylhet is also
explained in accordance with the evidence as to the spread of
the disease given in the last section. The true place and
cause of the orgin of the disease still remains to be demon-
strated, and for this purpose it will be necessary to go back
a little further both as regards time and place.

     When studying the literature of the subject in Calcutta
before commencing work in Assam, I was struck by the
general resemblance between the so-called "Bardwan fever"
of the sixties and early seventies and the descriptions of
kála-ázar, and some time afterwards it occurred to me that
the latter epidemic might possibly be a continuation of the
former. I therefore applied for the older Bengal sanitary
reports, and found that just about the time the fever was
dying out in Bardwan itself, there was a marked increase of
fever in the districts to the north, extending right up to and
including Dinajpore and Rungpore. Owing to the vital statis-
tics being only started in 1870 and to the frequent changes
in the manner in which they were collected in different years,
rendering it difficult to compare the prevalence of fever year
by year, and the further fact that no reports were received
from the Civil Surgeon of one of the districts during several
of the worst years in the northern part of the affected tract
of country, it was not easy to trace the exact sequence of
events. However, a minute study of all the material available,
together with a tabulation of such mortality returns and
meteorological data as were recorded, and a comparison of
these with the more accurate figures of recent years, has shown
that the fever epidemic in the north-western part of Bengal
in the seventies was independent of the "Bardwan fever,'
and was started by a succession of several years of very
deficient rainfall, such as is to this day commonly followed
by an unusual amount of fever in these parts. As the