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species of the same genus and such entirely different ones as 
Stomoxys^ and Tabanus. While arguing by analogy is often a 
fallacious method, some proof tiiat in this particular instance it can 
be accepted is afforded by the recent demonstration in Uganda that 
Trypanosoma gambiense can be transmitted by Gl. fusca}^ 
This question of exactly what species of biting flies, more 
particularly tsetse, are capable of transmitting human trypanosomiasis 
is one of the most important whicli still remains to be decided in 
connection with this disease. If it can be shown that Glossina 
pal Palis is directly responsible for the spread of the disease and that 
the other species are only accidental carriers, the work of controlling 
the extension will be very much simplified and the cost greatly 
lessened. This is a point which merits attention from all the 
Governments concerned. 
In brief, our knowledge as to the transmission of the disease 
stands thus — 
1. The only known method of transmission is mechanical. 
2. Gl. pal Palis and Gl. fusca can transmit the disease. 
3. At present all other species of Glossina must be regarded 
with equal suspicion. 
PROPHYLAXIS 
The whole system of prophylaxis is based on the application of 
gland palpation and puncture. Since by this means we are enabled 
to detect the disease in its earliest stages in over 97 per cent, of the 
cases, we are in a position to weed out the infected and isolate them 
before they have become very dangerous. It is manifest that as long 
as the trypanosomes are confined to the glands, as opposed to the 
peripheral blood circulation, the chances of a tsetse fly becoming 
infected are comparatively small. Koch’^ has also stated that the 
tsetse flies he employed only became infected when animals were used 
which had had the disease for a considerable length of time, and in 
whose blood the parasites were scanty. From this it will be seen 
that the value of gland palpation is enhanced so far as prophylactic 
measures are concerned. These measures may be divided into two 
broad sections— i major, and 2 minor measures. 
