CHEMOTHERAPY OF TRYPANOSOME AND SPIROCHETE INFECTIONS : BIOLOGICAL SERIES. I. THE TOXIC ACTION OF N-PHENYLGLYCINEAMIDE-p-ARSONIC ACID.

The essential facts to be gathered from these studies of the toxicologic action of N-phenylglycineamide-p-arsonic acid may be summarized very briefly. The substance is one which lends itself well to almost any method of administration and can be given to animals in very large doses. The tolerance of different animal species varies rather widely but with one exception the reaction of laboratory animals to toxic doses of the drug is of favorable character. That is, toxic effects are confined to doses relatively close to the minimum lethal dose and the recovery of animals from sublethal intoxications is remarkably rapid and complete. This feature of the action of the drug makes possible the repeated administration of even very large doses at comparatively short intervals of time without incurring the dangers incident to cumulative action or to superposition of toxic effects. On the contrary, by taking advantage of this peculiarity of action, it is possible to develop such a degree of tolerance on the part of animals that the dose of the drug administered can be progressively increased to a point well above that which is fatal to the normal animal, and this stands out as the feature of the toxicologic action of N-phenylglycineamide-p-arsonic acid which is of greatest significance in the use of the drug for therapeutic purposes.