76 
Surra 
Continuous treatment with atoxyl for long periods failed to effect a 
cure. During the period of treatment trypanosomes remained absent 
from the circulation, but reappeared in every case shortly after treatment 
was discontinued. 
Contrary to the experience of other workers, our experiments have 
indicated that arsacetin is equal in toxicity to atoxyl, and its administra¬ 
tion has much the same effect on the trypanosomes. 
In one case, pony no. C 30, where arsacetin was given in a single 
dose, which produced toxic symptoms, a cure has been effected. 
Soamin. From the results of our experiments, I conclude that soamin 
is about equal in value to atoxyl. It is equally toxic when injected sub¬ 
cutaneously, but, administered by the mouth, it appears to be much less 
toxic than atoxyl. 
In one case, pony no. C 31, where soamin was given in a single dose, 
which produced temporary paraplegia, the animal completely recovered 
and has shown no return of trypanosomes for eight and a half months. 
Mercury. Mercury alone has little effect on the course of the disease. 
In combination with atoxyl the results were not so good as when atoxyl 
alone was used. 
Antimony salts. Tartar emetic, in l°/ 0 solution, injected intra¬ 
venously, has a rapid but temporary effect on the trypanosomes in the 
circulation. 
Administered by the mouth, it has no influence on the course of the 
disease. Injected subcutaneously in very dilute solutions, it causes local 
irritation, frequently followed by necrosis of the skin, at the seat of 
inoculation. 
The sodium antimonyl tartrate and lithium antimonyl tartrate gave 
no better results than the potassium salt, and were equally irritant when 
injected subcutaneously in horses and rats. 
The combination of tartar emetic and mercury kept the circulation 
free from trypanosomes during the period of treatment only. A similar 
result followed the employment of tartar emitic and atoxyl, also of tartar 
emetic and arsenious acid solution. One pony, no. C 32, was cured by 
the treatment with tartar emetic, atoxyl and arsenious acid. The cura¬ 
tive effect was probably due to the arsenious acid. 
Arsenious acid. Ten cases, treated with arsenious acid alone, are 
recorded. In eight cases (C 1 to C 8) treatment has been successful. 
Five of these received ten doses, one eight, one five and one was cured 
by a single dose of arsenious acid. Two received four doses only and had 
a relapse. The arsenious acid was given in full sub-toxic doses at an 
