TRYPANOSOMES, TRYPANOSOMIASIS, AND SLEEPING SICKNESS 53 
The drug was used only upon animals showing the effects of the parasites, such as 
loss of weight, anaemia, fever, and autoagglutination of the corpuscles, and no animal 
was used until its blood contained numerous parasites. The numbers of the parasites 
present differed according to the species of animal and the disease. In the majority 
of the experiments control animals which were not treated and had been inoculated 
at the same time as the treated animals were used. In all cases the control 
animals died. 
Intravenous inoculation was used only on rabbits, all other animals were injected 
subcutaneously. Treatment was continued for one to three months or until increase 
of weight, diminution of the anaemia and entire absence of parasites from the blood, 
as far as microscopical examination could determine, was noted. At various periods 
susceptible animals were inoculated with the blood from a treated animal. When 
treatment had been discontinued for one to three months or longer, the animal 
was bled or killed and all the blood available was used to inject susceptible animals. 
Inoculated animals whose blood has given negative results after three to six months 
or after longer peripds have been inoculated with virulent blood and have taken the 
disease, thereby showing that no immunity was conferred by the previous inoculation. 
T. gombiense. — Rabbit, $, weight, 2,010 grammes. Parasites appeared on the 
twelfth day. On the forty-sixth day, numerous trypanosomes were present ; it had 
lost weight (1890 grammes). A blood count gave reds, 4,980,000 ; whites, 
8,860 ; haemoglobin, sixty-seven per cent. For three-and-a-quarter months it 
received ro c.c. of five per cent, solution atoxyl three times a week, gradually 
increasing the amount to I'O c.c. of ten per cent, solution. It then weighed 2,ood 
grammes. The blood count was : reds, 6,640,000 ; whites, 6,200 ; haemoglobin, 
eighty-eight per cent. The blood in quantities of ten c.c. was non-infective. The 
autoagglutination of the corpuscles was lost. Thirty-two days later it was very ill ; 
it was therefore bled to death, and the whole of its blood injected into a monkey. 
This monkey has never become infected. The post-mortem showed severe 
haemorrhagic cystitis, the bladder in parts being almost gangrenous and acute septic 
peritonitis, especially around the bladder. The spleen showed no congestion, but 
the connective tissue was slightly increased. The kidneys and liver were normal. 
Rabbit, 889, inoculated October 26 ; weight, 1,760 grammes. Blood count : 
reds, 6,620,000 ; whites, 6,700 ; haemoglobin, eighty-nine per cent. Parasites were 
seen from November 8 up to January ro ; the trypanosomes were always present, but 
in small numbers ; they then increased to eighteen to twenty to a field. The 
anaemia was pronounced, and loss of weight was noted. It then weighed 1,540 
grammes. Blood count : reds, 3,880,000 ; whites, 1 r,8oo ; haemoglobin, sixty- 
three per cent. It could hardly sit up, and remained most of the time lying down. 
This animal was given 0'8 c.c. of five per cent, solution atoxyl. At the end of 
eighteen hours the parasites were absent from the blood. Doses were given twice a 
