30 STRONG AND TEAGUE. 



and containing about 38 per cent of metallic arsenic (atoxyl contains 

 about 31 per cent) . 



It lias the following formula : 



As =As 



I I 



I I 



NH NH 



I I 



CH„ CH, 



I I 



COONa COONa 



It is considerably less toxic than atoxyl. 



The drug was received in sealed glass vacuum tubes. Since it is 

 readily oxidized to a much more toxic, brown substance when exposed to 

 the air. it should be dissolved and used immediately after such exposure. 

 The most favorable strength for injection is from 5 to 10 per cent. It 

 may be given either subcutaneously or intravenously. In man, sub- 

 cutaneous injection at times calls forth a marked local reaction with 

 subsequent abscess formation. This local reaction is sometimes depend- 

 ent, according to Ehrlich, upon too strong an alkalinity of the preparation. 



Although we now have been experimenting with arsenophenylglycin 

 in the treatment of trypanosomiasis for nearly a year, we have made no 

 previous publication of our results, because we wished to wait until the 

 work had been carried on in sufficient detail and for a sufficient length of 

 time to enable us to draw definite conclusions. A study of the literature of 

 the treatment of trypanosomiasis reveals the fact that many of the publi- 

 cations on this subject have been premature. Eemarkable claims have 

 been made in turn for each method of treatment, which have not been 

 borne out by more detailed and extensive experiments carried on for 

 longer periods of time. 



Our work with this drag has been confined entirely to monkeys, 

 horses and cattle. In our opinion nothing would be gained by experi- 

 menting with smaller animals, since several other methods of treatment 

 had already given satisfactory results in mice and rats, but these had 

 failed to cure the larger animals. 



It will be seen from our results with monkeys and horses that arseno- 

 phenylglycin is the most nearly ideal drag in the treatment of trypano- 

 somiasis that we as yet possess. While our work with this preparation 

 was in progress, several publications on the value of this drug in the 

 treatment of experimental trypanosomiasis in animals have appeared and 

 these will now be reviewed briefly. 



Wendelstadt and Koehl have both shown that a single injection of arsenophenyl- 

 glycin is capable of curing severe trypanosoma infection in mice and rabbits. 

 Eoehl has also demonstrated the prophylactic effect of the drug in these animals. 



