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houses. One of the most striking facts in connection with this disease, as I
have already mentioned, is that it never tends to spread from one person to
another in the same house, during the same season. Over 50 histories exempli-
fying this fact were carefully studied, and no better example could be given
than the following case. An Indian Salt official was transferred for duty to
Cambay in March 1909; he was accompanied by his wife, widowed sister and
her two sons. The first few days in Cambay they resided in the town, in the
house of an old resident, later going into a house which had been unoccupied
for a long time. While staying in the friend's house they were severely bitten
by bugs. About August the man, his widowed sister, and her elder son con-
tracted the disease almost simultaneously, the wife and the other nephew
escaping. The man had two large sores which lasted nearly two years, yet his
wife who occupied the same room, and even the same bed, did not develop
Oriental Sore till a year later, and the little nephew at the same time; the
latter case I had the opportunity of examining in its early stage. Numbers of
cases were studied in which there was one child who had Oriental Sore in a
house and several others who did not contract the disease till years afterwards.
This peculiarity in the spread of the disease cannot be overlooked, and in my
opinion it points very clearly to the transmission of the parasite by a blood.
sucking insect, in which development of the parasite takes place slowly, and.
that once that insect becomes infective, it may remain so for a long period, thus
being able to infect several people or the same person in more than one place.
It also suggests that the insect in question is usually transferred from one house
to another before it is infective. The last case studied in Cambay had. four
sores of the same age on his right arm, three of which were on the inner side of
the forearm, about three inches apart. This fact suggested that they were
acquired at the same time; it is necessary then to consider what blood
sucking insect will bite three adjacent parts of the body consecutively. The
only likely insects are mosquitoes and the bug. It is true that when a mosquito
is disturbed in the act of biting, it may quite possibly alight close to the spot
where it was first feeding, and that if disturbed again it may return to another
adjacent spot a few inches away from the former ones. Any one who has
observed the habits of mosquitoes will, I think, agree with me that the chances
of this happening are small; most mosquitoes when disturbed fly a considerable
distance, and when they again alight, select a more distant part of the body.
The only mosquitoes, as far as I am aware, which do return to the same place
are those belonging to the genus Slegomyia; I frequently observed this habit
exemplified in the case of the species prevalent in Cambay, and this was one
of the reasons why it was carefully studied. As far as the parasite of Oriental