228 Major R. Ross and Mr. J. G. Thomson. | Oct. 13; 
of the disease, but that it is often necessary to give large doses, namely, 
1 gramme, which imperil vision. These authors, however, still admit that 
permanent cure is a doubtful matter, and Sir David Bruce says that 
so far as we know the death-rate from Sleeping Sickness seems to be 
100 per cent. 
In the experiments made by us we subinoculated rats with the Rhodesian 
strain of trypanosomes from the patient W. A. at the Royal Southern 
Hospital, in order that we might determine the effect of atoxyl on this 
particular form of trypanosomiasis, which, as will be seen from the 
accompanying paper on enumerative methods in untreated animals 
(Fantham and J. G. Thomson),* was of great virulence. 
Eight rats were subinoculated with the Rhodesian strain from the patient 
(W. A.) at the Royal Southern Hospital. Four were treated with small 
doses of atoxyl, three were treated with large doses, and one was 
untreated. 
(1) Small Doses of Atoxyl—The weight of four rats treated with small 
doses varied from 139 grammes to 256 grammes. Take the body weight 
of a man as being 70 kilogrammes, and we find that the doses we administered 
to these rats would be represented in man by doses varying between 
4°55 and 25°14 grains. 
fats treated with above Doses of Atoxyl. 
Rat. | Colour. Weight. Duration of life. 
grammes. days. 
34, Picbaldies: ces 139 2 Animal house. 
35 iii Bos 145 26 Cold chamber. 
36 WV ihite .# arse 251 27 4, 
37 Seka ahe eee tae | 256 8 Animal house. 
Conclusions. 
Small repeated doses of atoxyl in this strain, z.e. the Rhodesian strain, 
prolong the life of the host, probably because of the tonic action of the 
atoxyl. Two of the above rats treated with atoxyl lived 27 days, and one 
lived 26 days. The last only lived 8 days, but, unfortunately, this animal 
contracted pneumonia. When we compare this with the life of the 
untreated animals inoculated with this strain we find that in 22 rats 
inoculated, the longest life recorded is 18 days, and thé average life of the 
22 controls was 11:3 days (Fantham and J. G. Thomson). Atoxyl, therefore, 
in small doses, undoubtedly prolonged the lives of Rats 34, 35, and 36. 
* © Roy. Soc. Proc.,’ B, vol. 83, pp. 206 —211. 
