316 Col. Sir D. Bruce and others. Antelope asa _ {|Nov. 9, 
The buck was fed on for six days (May 2—‘, inclusive) by laboratory-bred Glossina 
palpalis known to be infected with a human strain of Trypanosoma gambiense. 
On May 12, 1910, the tenth day after the infected flies’ first feed, Trypanosoma gambiense, 
in scanty numbers, appeared for the first time in the blood of the buck. On May 13, the 
trypanosomes being numerous in the blood of the buck, a few drops of its blood were 
injected, subcutaneously, into anormal white rat. This rat showed numerous 7rypanosoma 
gambiense in its blood on May 20. 
Result.—Positive. 
Remarks.—On its arrival at the laboratory the buck was free from trypanosomes 
inoculable into rats. Trypanosoma gambiense appeared in the buck’s blood, in scanty 
numbers, for the first time on May 12, and were present in large numbers on May 13 
and 14, 
We have now to record one of the most important and suggestive observations in this 
series of experiments. From May 14 to June 27 the blood was examined almost daily, and 
on the latter date—June 27—44 days after trypanosomes were last seen, Trypanosoma 
gambiense reappeared for one day in this buck’s blood in fair numbers. Their identity was 
established by careful examination in wet and stained preparations of the blood. 
(N.B.—Two mechanical transmission experiments were carried out with this buck. In 
the first, 50 flies were used and were fed on the buck for the three days the trypanosomes 
were seen in its blood. eswlt.—Negative. In the second, 100 flies were used, and were 
fed for four days on the buck. No trypanosomes were seen in the buck’s blood during 
these days. esult.—Negative. In the first experiment four hours, and in the second 
one hour, elapsed between the feed on the buck and the feed on the healthy monkey.) 
Experiment 2445. Reed-buck. 
No preliminary inoculation of this buck’s blood was made on its arrival at the 
laboratory. 
The buck was fed on for seven days (May 6 and 7, and 9—13, inclusive) by laboratory- 
bred Glossina palpalis known to be infected with a human strain of Trypanosoma 
gambiense. 
On May 14, 1910, the eighth day after the infected flies’ first feed, Trypanosoma 
gambiense appeared in the blood of the buck for the first time. On May 20 the buck 
died, and a small quantity of its heart’s blood was injected, subcutaneously, into a normal 
white rat. On June 2 rat showed Trypanosoma gambiense in its blood. (This rat was 
overlooked from May 24 to June 2, and its blood was not examined between these 
dates.) 
Result.—Positive. 
Remarks.—The blood of this buck was (with the exception of May 8) examined daily 
from May 6 to 13 with negative results for trypanosomes. On May 14, Trypanosoma 
gambiense appeared for the first time in its blood in scanty numbers ; on the 16th, 17th, 
and 18th they were very numerous ; on the 19th they were again scanty, and on the day 
of death, May 20, 1910, no trypanosomes could be found, the peripheral and heart’s blood 
being examined. 
Table I gives results of feeding infected Glossina palpalis on healthy 
antelope. 
