5 " 
Guinea-pigs. —Sub-inoculated with T. r bodes tense 
No. 
Incubation 
Duration of life 
Weight in grams 
Guinea-pig X 
... 13 days 
120 days 
35 ° 
Treated in Cold 
Chamber 
Guinea-pig 9 1 
... 6 days 
79 days 
3+6 
Treated in Animal 
House 
1 T hi» is Guinea-pig i in paper on Enumcrativc Studies on Trypanosomes by Fantham and 
J. G. Thomson. 
From the above tables it will be noted that the incubation period 
was delayed in all cases in the animals subjected to treatment in 
the cold chamber. 
In the above tables Guinea-pigs i, 2 and 3 were controls of 
Guinea-pigs 5 and 6. 
Guinea-pig 4 was control of Guinea-pig 7, and Guinea-pig 9 was 
control of Guinea-pig 8. 
The average incubation period of the five controls in the animal 
house was four days, whereas the average incubation period of the 
four animals treated in the cold chamber was 13^ days. 
The average duration of life in the controls was 64^ days, 
whereas in the animals treated in the cold chamber the average life 
was 97 4 days. 
In addition to this the animals in the cold were livelier, and took 
their food better than those in the animal house. 
We can, therefore, conclude that in guinea-pigs sub-inoculated 
with both strains of sleeping sickness we had the incubation period 
delayed in the cold, and also the life of the animals prolonged 
when treated by cold. 
We now experimented with rats. Here, again, we sub-inoculated 
the animals with the T. rhodesiense from the patient W.A., and we 
also sub-inoculated a scries of rats with the old laboratory strain 
of T. gambiense. 
Controls. Old Laboratory Strain. T. gambiense 
Number 
Piebald Rats 
Weight 
in grams 
Incubation 
Duration 
of life 
Number of 
Trypanosomes 
inoculated 
Number of 
divisions in 
first 24 hours 
Rat 23 . 
'73 
6 1 
'9 
2,000,000 
8 
Rat 27 . 
60,000 
7 
113 
5 
i 5 
17 
3 
60,000 
Rat 28 . 
IOI 
5 
