34 STRONG AND TEAGUE. 



We believe, therefore, that a number of our monkeys which, although 

 cured, finally died after long periods of captivity, could have been kept 

 alive by placing them under better conditions with regard to food and 

 environment and that this should be kept in mind in studying the tables. 

 Monkey No. 4432, although still free from parasites, was losing in weight 

 and strength and, in view of the possible existence of a latent infection 

 with surra, on October 12 a dose of 0.15 gram per kilo of arsenophenyl- 

 glycin was administered. This monkey was found dead on the morning 

 of October 22, 1909, its blood having been examined on October 21 with 

 negative results. It seems extremely probable that if the third treat- 

 ment had been omitted and this monkey had been placed under more 

 favorable conditions, it would not have succumbed. 



Of the monkeys receiving 0.07, 0.08, and 0.09 gram per kilo, some 

 were permanently cured by the single inoculation, while others suffered 

 a relapse and were treated a second time with a larger dose. Four of 

 these monkeys have remained free from trypanosomata for eight and 

 two-thirds months after a single treatment with the drug. 



A summary of the experiments of Series I shows that a single injection 

 of 0.04 to 0.06 gram of arsenophenylglycin per kilo of body weight 

 causes a disappearance of the trypanosomata from the peripheral cir- 

 culation, but that the parasites reappeared after a variable length of 

 time : that a dose of 0.07 to 0.09 may effect a permanent cure or may 

 not, but that the majority of monkeys so -treated recover. Furthermore, 

 not a single relapse occurred after the administration of 0.0S grata per 

 kilo as a second treatment. 



Series II. — The surra trypanosoma employed in this series was 

 obtained from a native pony that had acquired the infection under 

 natural conditions. An American horse was inoculated subcutaneously 

 with the blood of this pony and six days later his blood was used for 

 the inoculation of the monkeys. On August 4, 1909, 1 cubic centimeter 

 of the horse's blood was suspended in 20 cubic centimeters of salt solu- 

 tion and 2 cubic centimeters of the suspension given subcutaneously 

 to each of the 8 monkeys. The untreated control monkey died of the 

 infection twenty-six days after the inoculation. The other monkeys were 

 treated on August 10, 1909, and all were given a dose of 0.08 gram of 

 arsenophenylglycin per kilo; only one of these (No. 4559) was definitely 

 shown to have suffered a relapse. One animal, No. 4561, received only 

 a single injection of the drug and is still alive, seven months after the 

 treatment. The majority of the other monkeys were given a second treat- 

 ment with a larger dose (0.1 to 0.15 gram per kilo) ; one of these is still 

 alive, the others, apparently on account of their weakened condition, 

 succumbed to the toxic effects of the drug. 



Monkey No. 4565 was free from trypanosomata November 16 (three 

 and one-half months after treatment) ; it has since escaped. 



