40 STRONG AND TEAGljE. 



The course of the disease in this animal proved the virulence of the strain 

 employed in the further experiments. 



Horse No. 14. — American horse (weight 431 kilos) ; infected artificially on 

 July 12 by subcutaneous injection of 10 cubic centimeters of the blood of horse 

 No. 13. July 21 numerous trypanosomata were present in the animal's blood. 

 On July 22 an injection of 28 grams of arsenophenylglycin in 300 cubic centi- 

 meters of salt solution was given intravenously (0.065 gram per kilo). The 

 trypanosomata disappeared from the blood and did not reappear. The animal 

 was found dead on August 15. The cause of death in this instance is obscure, 

 but was probably due to the toxic effect of the drug. The horse died quite sud- 

 denly, having appeared to be in good condition on the previous day, when he 

 suddenly fell to the ground. 



Horse iVo. 15. — American horse (weight 375 kilos) ; infected artificially with 

 2 cubic centimeters of the blood of horse No. 14, containing numerous trypanoso- 

 mata. Five days later parasites were present in the blood of the animal and 

 the following day they were numerous. On this date the animal was given 25 

 grams of arsenophenylglycin intravenously (0.066 gram per kilo). On July 29, 

 two days later, this animal died of arsenic poisoning. 



Horse No. 16. — American horse (weight 502 kilos) ; infected with 2 cubic centi- 

 meters of the blood of horse No. 14 on July 22. On July 26 the blood of this 

 animal was positive for trypanosomata. On July 29, 11.5 grams of arsenophenyl- 

 glycin were injected intravenously (0.05 gram per kilo). The parasites were 

 absent from the blood of the animal on August 3. Although the blood was 

 negative for parasites, the animal appeared sick and did not eat well. For this 

 reason a second injection of 10 grams of arsenophenylglycin was given intra- 

 venously. Following this injection the horse suddenly became weak, staggered 

 and fell to the ground. The animal died on August 9 of arsenic poisoning. 



Horse No. 17. — American horse (weight 460.4 kilos) ; infected with 2 cubic 

 centimeters of the blood of horse No. 16 on July 29. On August 2, blood posi- 

 tive for trypanosomata. On August 7, 23 grams of arsenophenylglycin were in- 

 jected intravenously (0.05 gram per kilo). The trypanosomata disappeared 

 from the blood and remained absent until August 30. On August 30 the blood 

 was positive for trypanosomata and the animal was killed. 



Horse No. IS. — American horse (weight 466.8 kilos) ; infected artificially with 

 5 cubic centimeters of the blood of horse No. 17. On August 10 trypanosomata 

 were present in the blood of this animal and it was treated with 1,250 cubic centi- 

 meters of 0.5 per cent potassium antimonyl tartrate to which hydrogen sulphide 

 had been added and then carbon dioxide had been passed through the solution to 

 remove the excess of hydrogen sulphide. The trypanosomata disappeared from 

 the blood and remained absent for fifteen days 'when they again reappeared 

 in large numbers. On the same day 1,500 cubic centimeters of the same solution 

 were injected. The animal was found dead on the following day, death being 

 due to antimony poisoning. 



Horse No. 19. — Native horse admitted on October 18, having acquired the 

 surra infection naturally. Numerous trypanosomata were present in the blood. 

 On October 27, when the disease was well advanced the animal was killed. On 

 October 19. 5 cubic centimeters of this animal's blood, which contained numerous 

 trypanosomata, were injected into horse No. 20. 



Horse No. 20. — Infected with 5 cubic centimeters of the blood of horse No. 19. 

 On October 27 trypanosomata were numerous in the blood, when 30 grams of 

 arsenophenylglycin were injected intravenously (0.052 gram per kilo). Following 

 the inoculation the parasites disappeared from the circulation. Although the 

 animal's condition appeared good, after the injection diarrhoea developed and 



