d135 
Further Researches on the Development of Trypanosoma gambiense 
m Glossina palpalis. 
By Colonel Sir Davin Bruce, C.B., F.RS.,. A.M.S.; Captains A. E. 
Hamerton, D.S.O., and H. R. Bateman, R.A.M.C.; and Captain F. P. 
Mackig, I.M.S. (Sleeping Sickness Commission of the Royal«Society, 
Uganda, 1908-10). 
(Received February 15,—Read March 16, 1911.) 
The object of these experiments was to try to discover if there is any 
definite cycle of development of the trypanosome of Sleeping Sickness in the 
tsetse fly, Glossina palpalis, and if the late or renewed infectivity of the fly 
coincides with any phase in this development. , 
The mode of experimentation was to feed a cageful of laboratory-bred 
tsetse flies on an animal whose blood contained numerous trypanosomes, and 
at the end of various times to kill the flies and examine their intestinal 
contents. This was done for periods of one day, two days, three days, and 
so on, up to 56 days. The microscopical examination of preparations made 
from the intestinal contents on the various days gave information as to the 
number and appearance of the trypanosomes. 
After the infective feed or feeds the flies were fed every day on a healthy 
animal, so that by the appearance of trypanosomes in the animal’s blood the 
day on which one or more of the flies became infective could be arrived at. 
MeEtTHop USED IN THE EXAMINATION OF THE FLIES. 
The flies were killed by exposing them to the vapour of chloroform. 
After being killed the proboscis and pharynx were removed and examined 
under a cover-glass with the high and low powers. The terminal segment 
of the abdomen of the fly was then snipped off, and the whole abdominal 
viscera gently pressed out. This was moistened with a little normal saline 
solution, and the gut unravelled without rupturing. The proventriculus and 
crop were often pulled out intact with the gut. The whole thoracic and 
abdominal tract could then be laid out in line and examined under.a low 
power. 
In taking out the gut it was generally possible to draw out with it the 
abdominal portion of the salivary glands, which could then be separated 
without contamination from accidental rupture of the gut. If the salivary 
glands or proventriculus remained behind they were dissected out after 
removal of the gut. In every case these organs were thoroughly washed in 
