46 STRONG AND TEAGUE. 



phenylglycin on hand to continue the treatment of all of the animals, 

 some were destroyed. A few other horses died from the toxic effects of 

 the drug. There remained, then, on November 19 only 8 horses alive. 

 Four of these were brought to Manila and placed in screened stalls. 

 These latter have all remained entirely free from parasites for six 

 months 2 and are in excellent condition at the present time. The blood 

 of these horses has been subjected to repeated examination and as large 

 an amount as 20 cubic centimeters has been repeatedly inoculated at in- 

 tervals into monkeys with negative results. 



One of the horses, No. 73, had a slight rise in temperature on Decem- 

 ber 13; fearing a relapse, this horse's blood was at once injected into a 

 monkey and the horse was then given a full dose of arsenophenylglycin. 

 The monkey, however, remained free from trypanosomata, and we 

 feel justified in concluding that the rise in temperature was due to 

 Borne other cause than trypanosomiasis. These horses, we believe, have 

 been cured of surra. One of them has been kept at work for over a 

 month at Manila. Of the other horses, 2 have shown a reappearance 

 of trypanosomata in the peripheral blood after having been free 

 from parasites for three months and five months, respectively. In 

 view of the fact that the horses which were brought to Manila and 

 kept in screened stalls have not shown any relapses, and, also, because 

 the 4 horses left at Alabang remained in the same corner of the farm 

 where the horses infected with surra were originally segregated, it seems 

 not unlikely that the reappearance of the trypanosomata in the two 

 instances just cited resulted from a reinfection from biting insects and 

 was not due to a relapse of the original infection. However, it is pos- 

 sible that a relapse may have occurred. Both of these horses were 

 subjected to further treatment; one succumbed a day or so after the 

 administration of a large dose of arsenophenylglycin, the other is still 

 alive and in good condition three months after the last treatment. 



The other horses at Alabang, although negative for trypanosomata, 

 were treated on November 19 as a prophylactic measure because of their 

 intimate contact with the horse showing trypanosomata in its blood. 

 They have remained negative for trypanosomata and are in excellent 

 condition at the present time. They have not been under daily observ- 

 ation, as have the horses that were brought to Manila, but we are inclined 

 to regard them as free from the disease. 



We believe, then, that we have on hand 7 horses, all in good condition, 

 which have been definitely and permanently cured of surra by the in- 

 travenous administration of arsenophenylglycin. 



Surra runs a very chronic course in cattle in the Philippine Islands, 

 the animals harboring the parasites over long periods of time, during 

 which their general health may remain unimpaired. This renders it 



2 At the time of the reading of this proof, now 9 months. 



