360 
T. gambiense. Five experiments. Parasites usually present only 
in very small numbers or absent. Disease very chronic. Incubation 
period, three to forty days; average fifteen days. Duration, 
forty-two days to five and a half months; average more than four 
months. 
Table 6. —Guinea-pigs infected with 7 . gambiense 
Amount of virus 
injected subcutaneously 
or intrapcritoneally 
Day on 
which 
parasites 
were first 
seen in 
blood 
Day on 
which 
death 
occurred 
Remarks 
1. Intrapcritoneally. 1 c.c. of 
diluted blood solution con¬ 
taining (?) trypanosomes 
per c.mm. 
40th day 
134th day 
Parasites not found in blood (ex¬ 
cept on 40th day) until the last 
two days, when they were 
present in small numbers. 
» » 
3 rd „ 
167th „ 
Parasites rarely found in small 
numbers. 
3- Intrapcritoneally. 1 c.c. of 
diluted blood solution con¬ 
taining 10,000 trypanosomes 
per c.mm. 
7 th „ 
42nd „ 
Parasites regularly present, and 
sometimes in considerable num¬ 
bers (20 to 30 to a field). 
4 - » „ 
1 3th „ 
Parasites only found on three 
occasions in very small numbers- 
Animal alive and well after four 
months. 
5- Intrapcritoneally. 1 c.c. of 
diluted blood solution con¬ 
taining 1000 trypanosomes 
per c.mm. 
12th „ 
1 60th „ 
Parasites rarely found in very 
small numbers. 
Dogs. 
Rhodesian strain. Four experiments. The trypanosome proved 
to be extremely virulent in dogs. In Dogs 1 and 2, parasites were 
present in the blood in large numbers, and many posterior nuclear 
loims were seen. I rypanosomes, although constantly present, were 
never very numerous in Dogs 3 and 4, and none of the above 
varieties were observed. The animals rapidly lost their weight- 
Incubation, four to five days; average four days. Duration, nine 
to thirteen days; average twelve days. 
