All of our guinea-pigs infected with Trypanosoma brucei (strain “ferox”) died whether they were treated or not. It is evident that both tryposafrol and novo-tryposafrol exerted a directly injurious effect upon the guinea-pigs. Reckoning the day on which the guinea-pigs were inoculated as day 1, the 19 treated guinea-pigs died respectively on days 5, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 11, 18, 19, 19, 26, 27 and 33. The six untreated guinea-pigs died respectively on days 23, 25, 25, 27, 44 and 45. The two preparations of the dye are therefore worse than useless as remedies for Nagana in guinea-pigs.

Five dogs were infected with Piroplasma canis (Cambridge strain) of which four were treated and one not treated with novo-tryposafrol.

All of the dogs died although treatment was given under the most favourable conditions, starting on the day of inoculation. The four treated dogs died on days 12, 9, 17 and 12 after inoculation respectively; the untreated (control) dog died on the 13th day. The drug exerted no influence upon the course of the disease, nor upon the appearance of the parasites and their progressive increase in the blood. Novo-tryposafrol may therefore be regarded as useless in the treatment of canine piroplasmosis, and, judged from these results on dogs, it will no doubt prove to be equally useless in the treatment of bovine piroplasmosis when it has received a scientific trial in competent hands.

In view of the negative results obtained by ourselves and other independent investigators, working especially with trypanosomiasis, we conclude that the value of tryposafrol or novo-tryposafrol as a remedy for any of the diseases enumerated by the authors is open to grave doubt since the chief claims as to its efficacy were based on experimental results which the authors state that they obtained with Nagana.