TREATMENT OF TRYPANOSOMIASIS. 45 



having been treated for one month. On March 5, trypanosomata reappeared 

 in the blood. March 9, 24 grams of arsenophenylglyein were given intravenously. 

 The animal died four days later. 



Mule (American) Wo. 33. — Found positive for surra on December 28 at Bu- 

 lacan. Arsenic sulphide 20 grams by mouth. December 30, blood negative, ar- 

 senic sulphide 20 grams. Animal found dead on morning of January 1. 



Epidemic at Aldbang. — During the past year an epidemic of surra was 

 also observed among the horses of the Government stock farm at Alabang. 

 On September 3 we visited Alabang and found 17 horses infected with 

 surra. The blood in each instance was examined and the trypanosomata 

 found therein. In many of the animals the parasites were very numerous 

 and the horses showed well-marked symptoms of surra. In the following 

 few weeks 3 other horses were found infected with surra at Alabang and 

 these were treated with the others. The horses, during the course of 

 their treatment, were kept in an open field at one comer of the farm 

 and were fed under a nipa roof, which afforded some protection from 

 the sun. Plies were abundant, to the bites of which the horses were 

 naturally exposed. The conditions, therefore, were such as might be 

 met with in combating the disease in provincial districts with no, protec- 

 tion against reinfection, either from biting flies or from contact with 

 other infected animals. 



Therefore, the conditions surrounding the experiment seemed most 

 unfavorable for obtaining good results from treatment. 



The injections of arsenophenylglyein were given intravenously in ap- 

 proximately 10 per cent? solution. Since no facilities were at hand for 

 holding the horses while they were being treated, it frequently happened 

 that during the inoculation the needle escaped from the vein so that 

 some of the solution was given subcutaneously. When this occurred, 

 severe local reaction sometimes followed which resulted in abscess forma- 

 tion. However, the abcesses healed later without trouble. ISTo animals 

 apparently died from the local effect of the drug. Owing to the condi- 

 tions just described, it was impossible in the course of the experiments 

 to determine whether a reappearance of the trypanosomata in the blood 

 of individual horses indicated a relapse, or a reinfection. The experi- 

 ments- in monkeys indicated that a single large dose of the drug gave 

 the best results. However, owing to the fact that some of our horses would 

 almost certainly have been reinfected with surra during the period fol- 

 lowing the first treatment, we felt compelled to repeat the dose at in- 

 tervals, even though the blood remained negative in most of the cases. 

 Our experiments with horses have shown us that as few injections as 

 possible should be made, owing to the danger of the production by the 

 drug of grave lesions in the internal organs. Table III gives the results 

 of the treatment of these horses. 



Discussion of Table III. — During the few weeks following the first 

 treatment of the horses, trypanosomata reappeared in the blood of a 

 number of them, and since we did not have a sufficient quantity of arseno- 



