The animals used were guinea-pigs and rats, and we used two 
strains of trypanosomes— 
(1) The T. rhodesiense obtained from patient W.A. (Ross and 
Thomson, 1910*), and 
(2) An old laboratory strain of 7 '. gambiense. 
The essential differences between these two strains has been 
discussed by H. B. Fantham and J. G. Thomson in Paper on 
Enumerations in 1 Jntreatcd Animals suffering from Sleeping 
Sickness,’ 1910+. 
W’e at first selected guinea-pigs sub-inoculated with sleeping 
sickness, and from the tables we append it is evident that the 
animals were more resistant to the infection while living in the cold 
chamber. 
'T. gambiense. Old Laboratory Strain. Controls in Animal House 
Animal 
Incubation 
Duration of life 
Weight in grams 
Guinea-pig 1* ... 
4 
28 
495 
Guinea-pig 2 1 ... 
4 
3 ° 
580 
Guinea-pig 3- ... 
4 
105 
534 
Guinea-pig 42 ... 
2 
79 
403 
' Counts of these animals arc not given. 
Daily counts of these animals are given in 
somes in Animals by Fantham and J. G. Thomson, 
pig 4 1* numbered as 6. 
the paper on Enumerative Studies on Trypann- 
where Guinea-pig 3 is numbered as 7 and Gumea- 
T. gambiense. Old Laboratory Strain. Treated in cold. Lowest Temp. 20° F. 
Animal 
Incubation 
Duration of life 
Weight in grams 
Guinea-pig 5 
... 
•9 
102 
648 
Guinea-pig 6 ... 
6 
93 
562 
Guinea-pig 7 
16 
74 
623 
* D,.... ,, 
tp_ . B . c ' 5 B > VoL lxxxhi, PP . 187-205 (, 9 i,) 
rv — °- y ' K ‘ VoL r XXXrn - pp- 206-211 (1911), and Ann. Trop. Med. and Pa 
v , '„v oc - K °y- Soc -> 
Vo1 -' IV - PP- 417-463. 
