17

Microscopic examination of the gut and gut-contents
proved negative as regards developmental forms.

The following transmission experiments were carried
out with the object of ascertaining whether the trypanosome
undergoes any special development in the body of Stomoxys.
(The experiments were carried out and protected exactly as
in the case of the mosquito experiments, the flies being-
caught feeding on surra horses or surra camels with
trypanosomes in their blood at the time.)

Experiment VII.—Between 12th July and 1st September
a white rat (No. 2) was bitten by 30 Stomoxys (thus obtained
and treated) after an interval of 42 to 48 hours. Result
negative.

Experiment VIII.—Between 14th July and 11th
September a white rat (No. 3) was bitten by 15 Stomoxys
(thus obtained and treated) after an interval of 3 to 4 days.
Result negative.

Experiment IX.—Between 16th July and 13th Septem-
ber a white rat (No. 4) was subjected to 33 bites by Stomoxys
(thus obtained and treated) after intervals of 5 to 21 days.
The number of individual flies used was 10, and they
fed every 2 days on this rat from the 5th or 6th day follow-
ing capture until they died. Result negative.

The number of bites at different intervals is shown
below :—

I therefore obtained no evidence in support of the
fly as a surra transmitter depending on any cycle of devel-
opment, but a good deal against it.

MECHANICAL TRANSMISSION OF SURRA BY BITING-FLIES.

Tabanus has been proved by many observers to be
capable of conveying trypanosomiasis from one animal to
another, but it was absent during the latter part of the
Kathgodam outbreak, and further it has been proved capable