W. L. Yakimoff and others 
47 
After inoculation of the blood from mice infected with the “Bokhara - ' 
virus—intraperitoneally—trypanosomes appear in the blood after 3-4 days; 
subcutaneously—after 4 days. 
On the other hand, inoculating with the blood of mice infected with the 
virus of the “Samarkand” and “Termezh” strains, the period of incubation 
lasted from 4 to 6, and even 10 days. This is due, in our opinion, to the 
fact that the “Bokhara” virus had been invigorated by passage through mice 
for a long time, and had attained a high degree of virulency, whereas the 
virus of the “Samarkand” and “Termezh" strains had not been invigorated 
in this manner. 
After infection from the blood of mice, the guinea-pigs succumb in 13-23 
days, and after the appearance of trypanosomes in the blood—in 10-19 days 
(in one case the animal succumbed in 3 days). 
On inoculating guinea-pigs with infected blood from other guinea-pigs, 
trypanosomes appear in the circulation in 5-12 days after intravenous 
inoculation (in one case the period of incubation lasted 23 days), and 12 days 
after subcutaneous inoculation. 
Death occurred 10-33 days after inoculation, and 4-21 days after the 
appearance of trypanosomes in the blood. 
Lastly, a certain proportion of the guinea-pigs were infected by means of 
blood from rabbits (“Samarkand” virus). 
Here the trypanosomes appeared in the blood 4-H7 days after intra- 
peritoneal inoculation, and the animals succumbed 19-21 days after infection 
and 7-15 days after the appearance of the parasites in the blood. 
Summarising the above, it may be assumed that the course of the infection 
varies according to (1) the method of infection, (2) the quantity of trypano¬ 
somes introduced and (3) the virulence of the virus. Trypanosomes appear 
in the blood of the guinea-pig in 3-17 days, and death occurs 13-33 days 
after infection and 4-21 days after the appearance of trypanosomes in the 
blood. 
Trypanosomes are not always present in the blood of infected guinea- 
pigs. During the whole period of infection no external symptoms of the 
disease are observable. 
« 
( e) Dogs. These animals are very easily infected with trypanosomes. 
In one dog (No. 1) we carried on detailed observations on the tem¬ 
perature : 
At the very beginning (even at the first appearance of trypanosomes in 
the blood and during three days) it only rose a few tenths of a degree. On 
the 9th day (previously to the third appearance of the parasites in the blood) 
it rose above 40° 0. Thence, from the 10th day, till the 18th it was below 40°, 
and once (on the 11th day) it fell even to 38*1°. On the 19th day it rose to 
41°, to fall, however, on the next day to 38-8°. • 
Later the curve rose to a maximum of 41*5°, after which it remained 
