Cold Chamber. Old Laboratory Strain. T. gatnbtense 
Number 
Piebald Rats 
Weight 
in grams 
Incubation 
Duration 
of life 
Number of 
Trypanosomes 
inoculated 
Number of 
divisions in 
first 24 hours 
R « 45 . 
270 
7 
12 
2,000,ooo 
8 
Rat 46 . 
"3 
6 
2 6 
60.000 
Fall in first 2+ 
hours 
Animal House. 7 . rboJenenst 
Number 
White Rats 
Weight 
in grams 
Incubation 
Duration 
of life 
Number of 
Trypanosomes 
inoculated 
Number of 
divisions in 
first 24 hours 
Rat 17 . 
62 
4 
8 
38,000 
A fall 
Rat 16 . 
58 
4 
13 
200,000 
8 divisions 
Cold Chamber. 7 . rbodesieme 
Number 
White Rat 
Weight 
in grams 
Incubation 
Duration 
of life 
Number of 
Trypanosomes 
inoculated 
Number of 
divisions in 
first 24 hours 
R; *t 47 . 
9 ° 
6 
11 
38,000 
4 divisions 
It will be noted from the above that the average incubation 
period of those in the cold chamber was 6 3 days, whereas the 
incubation period of the control was 4 8 days. 
I he average life in the cold was 16 3 days, and the average of 
those in the animal house was 14 2 days. 
Rat 23 is the control of Rat 45. Rats 27 and 28 are controls of 
Rat 46. Rat 17 is the control of Rat 47. 
W e now append a table of the daily counts of the 
trx panosomes in the peripheral blood of animals treated in the 
. ° ‘ These counts were made every twenty-four hours. The 
incubation period is stated in days, and we define it as the period 
trypanosomes are first found in one quarter cubic millimetre 
of peripheral blood. 
