Nature of epidemic and method of infection.

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infected house or village in order to contract the fever. It
was also shown that the disease usually begins in one place by
a person who has contracted the fever in another coming to
live in the uninfected village, and that the next cases occur
in the same house as he is residing in, and then it spreads
to others, often those who frequently visit the first cases
when ill, being the next to suffer. The majority of new
cases begin during the rainy season, and there is always much
less fever in the cold-weather months, when the ground is
dried up. Further, the infection sticks to houses and the soil
of affected villages, and, in a few instances, where the inhabit-
ants of an entire village or coolie lines have been moved to a
new site, which may be only 200 yards from the old one, dur-
ing the cold-weather months, when the fever is at a minimum,
then the disease has not broken out in the same way among
them during the ensuing rainy season, as it had in previous
ones. This shows that they had left the infection behind them
in the soil of the old village site. How can all these facts be
explained? It is evident that the malarial germs must escape
from the bodies of those who are suffering from the fever in
some way or other. Dr. Patrick Manson and others have
recently suggested that this takes place in ordinary malaria
by mosquitoes sucking up the blood from infected persons,
and then going and dying in water in which the germs
contained in the blood that they have extracted escape
and multiply. Although Surgeon-Major R. Ross has recently
published some interesting experiments on certain changes
which the crescent-shaped form of the parasite goes through in
the stomach of the mosquito, there is as yet very little evidence
in favour of Dr. Manson's ingenious idea; and, although
I have constantly borne it in mind, I have not met with any
facts in the course of my investigation that lend support
to it. On the contrary, it would be very difficult or impos-
sible to explain the facts that I have adduced as to the
infection in kála-ázar on this hypothesis, while the crescent-
shaped bodies are not met with in kála-ázar, and even