No drug has been found which will influence the fatal course of East Coast Fever or retard the multiplication of Theileria parva in the blood of the affected cattle.

The drugs which were tried with negative results were Trypanblue, Congo red, Tryposafrol, Creosote and Oleum copaivae, Arsacetin, Soamin, “606,” Emetine hydrochloride, Mercury salicylate, Mercury succinimide, Quinine bihydrochloride and hydrochloride, Ethylhydrocupreine, Ammonium fluoride, Potassium iodide, Sodium salicylate, Calcium lactate, and Nuclein.

All of our animals died—18 treated and 3 untreated—and showed typical lesions at autopsy. They were all infected by means of ticks (Rhipicephalus appendiculatus) which had fed on infected cattle as larvae and nymphs and been placed on the experimental animals as nymphs and adults respectively.

The increase in the number of parasitized red blood corpuscles, but for slight irregularities, proceeds continuously night and day until the animal dies. We have not as yet observed a case ending in recovery.

The accompanying table gives a summary relating to each experimental animal (except XII): the number and kind of ticks which produced infection, the incubation period, the time when the parasites appeared in the peripheral blood, the time when the animals died, and the maximum percentage of parasitized blood corpuscles observed during the course of the disease. The days are all reckoned from Day 1 when the infective ticks were placed upon the cattle.