8

Many lice were bred, and then fed from the first instar up to the mature
insect. Their alimentary tracts, salivary glands, and other organs, were regular-
ly examined in fresh and in stained preparations, but not a single parasite,
either changed or unchanged, was found in any of them. I could therefore
come to no other conclusion but that lice (P. vestimenti and P. capitis) are not
the natural invertebrate hosts of the parasite. The statements of the people
themselves confirm these results; educated Indians of high caste, who wash
daily and change their clothes often, and who practically never harbour body lice,
and very seldom head lice, contract the sore as readily as people who never
wash and who harbour such vermin. Further, Europeans who have contract-
ed sores in Cambay, particularly the case of a lady who had one on her lower
lip, strongly oppose the idea that lice are the transmitters.

EXPERIMENT IV.

IS THE PARASITE TRANSMITTED BY ANY SPECIES OF MOSQUITO
OR OTHER BITING FLY ?

     In Cambay Stegomyia sp. was extremely common throughout the year;
it is a voracious blood sucker, often biting through clothes. A large number of
these mosquitoes were bred out in the laboratory, and fed in test tubes on the
case, some on the margin of the sore, and others on distant parts. They were
examined at regular intervals, but I was unable to find any parasites, either
changed or unchanged, in any of these mosquitoes; they were not infected
with a natural herpetomonas, which in the case of mosquitoes comes through
the larvæ. There was then no evidence whatever to shew that this species of
Stegomyia was the natural carrier.

     No other species of mosquito was experimented with chiefly for the reason,
that, as I was working single handed, I was unable to collect larvæ in suffi-
cient numbers to carry out experiments, and also for the reason that in Cambay
the localised nature of Oriental Sore strongly opposes the hypothesis that a
flying insect is the carrier. As I have pointed out ahove, the railway staff,
who live around the station, about a quarter of a mile from the endemic area,
never contract the disease. This is a very striking fact, for flying insects such
as house flies and mosquitoes, which may have become infected in the town
itself, would have every opportunity of biting people living just on the
outskirts.

     Phlebotomus sp., probably baba Annandale, was only seen during the rainy
season, June to September, and then in small numbers. I was bitten by a few
of these flies but with negative results; four specimens caught in the Hospital