TREATMENT OP TRYPANOSOMIASIS. 47 



extremely difficult to determine whether or not a drug used in the 

 treatment of these animals is efficacious. Therefore, although we have 

 treated a number of bullocks that were infected with the disease, we 

 prefer to express no opinion at this time with regard to the action of 

 the drug on these animals. v 



SUMMARY. 



In the use of arsenophenylglycin two methods of treatment may be 

 considered, as already outlined by Ehrlich : First, that by stages in 

 which relatively small doses are given and at repeated intervals; second, 

 the treatment by one or several large doses. In monkeys and horses 

 there is no question but that the second method of treatment is the more 

 favorable one. In horses, the most satisfactory results have been obtained 

 where we have given an amount probably very close to the fatal dose to 

 the animal infected. Unfortunately, in horses the margin between the 

 dose necessary to effect a complete cure and the fatal one seems very 

 small (see horse No. 21), too small for us to be able to determine the 

 amount most favorable for any given case. Moreover, the susceptibility 

 of horses to the effect of the drug naturally varies to some extent. 

 The condition under which the animal is kept after treatment, whether 

 favorable or otherwise, may possibly be the deciding point as to whether 

 the animal recovers or dies. Each repetition of a large dose obviously 

 exposes the animal to increased danger of poisoning, while the oppor- 

 tunity of producing a cure is diminished. These facts are evident upon 

 consideration of the action of atoxyl in the human body and from the 

 results of our own experiments. 



In conclusion, we do not hesitate to say that arsenophenylglycin has 

 proved to be by far the most satisfactory means of treatment of 

 trypanosomiasis yet discovered. The drug has shown itself to be very 

 efficacious for the treatment and cure of surra infection in monkeys. 

 However, while the results in horses, are the best that have as yet been 

 obtained, they are not nearly as encouraging as in monkeys. "We have, 

 however, for the first time been able to cure horses afflicted with surra, 

 and this we never could accomplish before by any other means. 

 While it appears that we can save a certain percentage of the horses 

 infected with surra during an epidemic, we can never predict with 

 certainty whether in a given instance we will be able to cure the horse, 

 or whether he will succumb first to the action of the drug. However, 

 since, the disease is invariably fatal in these animals without treatment, 

 a trial should be made in the case of every horse of any great value. In 

 the epidemic at Alabang, we were able to save a sufficient percentage of 

 the horses to demonstrate that the means is of some practical value in 

 the treatment of surra during an epidemic. 



It is not our intention in the present paper to report upon the results 

 we have obtained in the treatment of trypanosomiasis with a large num- 

 ber of other compounds prepared by Doctor Oechslin, of the chemical 



