90 
Surra 
Orpiment. 
In these experiments chemically pure arsenious sulphide was used. 
Pony no. 73. 250 lbs., received 6 gms. No effect on trypanosomes. 
Pony no. 74. 230 lbs., received 7 gms. Trypanosomes disappeared for 10 days. 
Pony no. 75. 307 lbs., received 8 gms. Trypanosomes disappeared for five days. 
Pony no. 76. 416 lbs., received 10 gms. Trypanosomes disappeared for eight days. 
Pony no. 77. 523 lbs., received 10 gms. Trypanosomes disappeared for seven days. 
Treatment with atoxyl and arsenic. 
Treatment was commenced at the first or second period of paroxysm, 
when trypanosomes were numerous in the circulation. Freshly prepared 
four per cent, solutions of atoxyl were used subcutaneously. Arsenious 
acid was administered in bolus. 
Several of the earlier experiments in which the animals died from 
over dosage are not here recorded. 
The first seven cases detailed are experiments in which the treatment 
did not meet with success ; the following nine are cases where the result 
has been successful. 
The atoxyl and arsenic were administered alternately, leaving one 
day interval between each dose. 
Pony no. 87. 300 lbs., 2nd paroxysm. 
1st day 50 c.c. atoxyl. 
3rd ,, 0-5 gm. ars. ac. 
5th ,, 50 c.c. atoxyl. 
7th ,, 0 - 5 gm. ars. ac. 
9th ,, 50 c.c. atoxyl. 
16th day of disease. (Intermittent dosage.) 
11th day 0-5 gm. ars. ac. 
13th ,, 50 c.c. atoxyl. 
15th ,, 0-5 gm. ars. ac. 
17th „ 50 c.c. atoxyl. 
19th ,, 0 - 5 gm. ars. ac. 
The trypanosomes disappeared after the first dose. Reappeared 
4 days after the treatment ceased. The dose of ars. ac. was insufficient. 
Pony no. 88. 600 lbs., 1st paroxysm. 
1st day 50 c.c. atoxyl. 
3rd ,, 2 gms. ars. ac. 
5th ,, 75 c.c. atoxyl. 
7th ,, 3 gms. ars. ac. 
9th ,, 100 c.c. atoxyl. 
4th day of disease. (Intermittent dosage.) 
11th day 2 gms. ars. ac. 
13th ,, 100 c.c. atoxyl. 
15th ,, 2 gms. ars. ac. 
17th ,, 100 c.c. atoxyl. 
19th ,, 2 gms. ars. ac. 
Trypanosomes disappeared from the circulation after first dose, but 
reappeared 7 days after last dose. 
