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SECTION VII.

ON THE COMMUNICABILITY OF KÁLA-ÁZAR.

     We have seen in the last section that the general distribu-
tion of kála-ázar is that of a communicable disease, and that
it always spreads along the lines of traffic or human inter-
course, while it is checked by any tract of uninhabited country
through which there is no road; that it has crossed the
Brahmaputra river on several occasions, always in the lines
of the greatest traffic, and that the way it has gradually
crept up the Assam Valley, cannot be explained on any
local change of the soil or sanitary conditions of the affected
districts, while the natives themselves, and also many of
the Europeans who have come into intimate contact with
the disease, agree in believing that the disease is in some way
communicable from man to man, while this opinion was
confirmed by Dr. Giles as a result of his investigation in
1889-90. It is then of the first importance to try and trace
in what way the disease is transmitted from place to place.
In order to ascertain in what way, if any, its progress can be
checked, for it is evident that its spread cannot be explained
on the ground of its being anchylostomiasis, as this is not the
cause of the affection.

     That this has not yet been done, and that there are some
who are still sceptical as to the disease being communicable
at all, is due to the great difficulties in tracing the spread
of an affection, which must be present in any individual case
for a long period, always several weeks, and often two or
three months before it is recognisable from such a universally
present disease as ordinary malarial fever, and from which
it may, individually considered, be absolutely indistinguish-
able throughout its whole course, and sometimes whose very
presence in a village, or even on a tea garden, has not been
recognised until it had produced a great increase in the death-
rate, which may take it at least a year to bring about. When

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