38 STRONG AND TEAGtJE. 



jected subcutaneously. Considerable cedema at the site of the injection on the 

 following day. 



May 3. monkey was inoculated with 30 cubic centimeters of the blood of the 

 horse, but no trypanosomata developed in its blood. Following the inoculation 

 of the monkey 15 grams of the drug were given intravenously to the horse, 

 although the blood examination the previous day had been negative for parasites. 



May 12. a second monkey was inoculated in the same manner with the same 

 result. 



June 4, a third monkey was inoculated with 20 cubic centimeters of the horse's 

 blood, on the loth of June it developed trypanosomiasis and died on the 26th. 



This experiment demonstrates that this strain of trypanosoma had not lost 

 its virulence, although the animal from which it was taken had received previously 

 2 doses of arsenophenylglycin. 



June 10, an examination of the horse's blood showed a few trypanosomata. 

 On the same day another inoculation of 10 grams- of arsenophenylglycin was 

 given intravenously. The parasites disappeared from the blood, but reappeared 

 on July when 11.4 grams of arsenophenylglycin were again given intravenously. 

 Although the trypanosomata did not reappear in the blood, there was given on 

 July 15 another dose of 10 grams of arsenophenylglycin intravenously and on 

 August 3, 11 grams more. Thirty cubic centimeters of the blood of the horse were 

 injected into a monkey on August 3 before the inoculation with the drug. The 

 animal later developed trypanosomiasis. On August 5 the horse was unable to 

 rise and on August 6 he died, evidently succumbing to the surra infection. Al- 

 though this animal was treated in a screened stable, nevertheless it was necessary 

 to place him alongside another animal which had surra and which remained 

 untreated. It is possible, therefore, that he may have been reinfected with 

 trypanosomiasis from the other surra animal. 



Horse No. 5. — Small bay horse; contracted surra naturally. At the time of 

 treatment, April 29, there was oedema of the abdomen and trypanosomata were 

 numerous in the blood. Ten grams of arsenophenylglycin were injected sub- 

 cutaneously. On the following day there was considerable oedema at the site 

 of the inoculation. On the day following the injection there was watery diarrhoea 

 which lasted about twenty-four hours. Although no trypanosomata reappeared 

 in his blood, he was given a second inoculation of 10 grams intravenously on 

 May 3. Following this, the animal was unable to stand and there was marked 

 tremor of the muscles. The animal died on May 8, evidently of arsenic poisoning. 

 Three monke3*s were inoculated with his blood, 1 on May 3 with 20 cubic cen- 

 timeters, 1 on May 7 with 10 cubic centimeters, and 1 on May 7 with 2 cubic 

 centimeters. None of these animals developed surra infection. 



Horse No. 6. — Native pony; contracted surra naturally. The duration of the 

 disease unknown, although the condition of the animal appeared to be good at 

 the time treatment was begun. On April 30 its blood was positive for trypanoso- 

 mata and 6 grams of arsenophenylglycin were injected subcutaneously, after which 

 the parasites disappeared from the circulation and did not reappear. 



On May 4, 15 grams of the drug were injected intravenously. On this date, 

 previous to the injection of the drug, a monkey was also inoculated subcutaneously 

 with 30 cubic centimeters of the horse's blood. This animal did not develop 

 surra. On May 10 there was considerable oedema along the lower margin of the 

 abdomen. The blood remained negative for trypanosomata. The animal died 

 May 28. The immediate cause of death of this animal is not clear. 



Horse No. 7. (Treated with arsacetin.) — Native horse which contracted the 

 disease naturally. Condition good at the time treatment was commenced. No 

 information was obtainable regarding the time the animal had been infected with 



