TRYPANOSOMES, TRYPANOSOMIASIS, AND SLEEPING SICKNESS 
doses given than with the standard ' Gunjur ' strain. Despite treating the animals 
early some died. With this strain treatment had to be kept up longer. Some rabbits 
have survived eight months after injection, while all the controls have died in fourteen 
to thirty-six days. Guinea-pigs infected with this strain do not react so well to the 
treatment. Rats must be treated early and with high doses if treatment is to be 
successful. Mice infected with this strain react if treatment is commenced early 
enough. 
T. brucei. — Guinea-pigs inoculated for two months. Average loss of weight one 
hundred and fifty to one hundred and ninety grammes. Parasites forty to sixty to a 
field. Initial dose, 0'4 c.c. five per cent, solution ; parasites absent in about eighteen 
hours. Treatment, two to three times a week, o*i of five per cent, solution. At end 
of two to three months treatment was discontinued ; the animals had increased in 
weight. At periods, one to two-and-a-half months after stoppage of arsenic, the 
animals were killed and their whole blood used to inoculate rats. None of the 
rats inoculated from these guinea-pigs have ever shown parasites. Some of the 
control rats inoculated during the first five weeks of the treatment have become 
infected after lengthy incubation periods. These treated guinea-pigs have shown 
increase of weight and lessening of the agglutination of the blood cells. Non-treated 
guinea-pigs have lived on an average forty to forty-five days. One treated pig had 
lived nine-and-three-quarter months since becoming infected, or five-and-a-quarter 
months since discontinuation of treatment. 
Rats. — Treatment was begun two to three and four days after parasites appeared, 
when the animals were in the last stage of the disease and showed the semi-comatose 
condition which is so often met with. Rats of one hundred and twenty-five grammes in 
this last stage, and showing two hundred or more parasites to a field, have been given 
0-5 c.c. of five per cent, solution. The parasites have been absent from the tail blood 
at the nineteenth hour. It treated twice a week with o - 3 of five per cent, solution, 
and the amount gradually increased, the parasites remain absent, the blood is non- 
infective and the animal puts on weight. Some have lived one hundred and twenty-six 
days from date of inoculation, and fifty-seven days after treatment was stopped ; they 
have succumbed to broncho-pneumonia or dysentery. The subinoculated animals have 
remained uninfected. Rats treated only once with 0-5 c.c. of five per cent, solution 
■show parasites in their blood again in six to eleven days, and unless treatment be 
recommenced, the disease will pursue its natural course. 
Cow. — This animal was inoculated subcutaneously from a guinea-pig. Parasites 
appeared on the sixth dav but were very scanty. A severe enteritis occurred on the 
ninth day, but the animal survived the attack. The parasites slowly increased. Loss 
of weight and marked anaemia developed. Parasites continued to increase, the animal 
was then given 1*5 grammes of atoxyl in ten per cent, solution subcutaneously. The 
parasites disappeared slowly. Leucocyte count increased. Deformed degenerated 
