54 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
week, beginning with 0-5 c.c, and increasing to 2 - o c.c. of a five per cent, solution. 
The blood in large doses is non-infective. The animal is vivacious ; the coat is 
smooth and thick. Average weight, sixteen hundred grammes. Several guinea-pigs 
infected for about two months, and showing twenty to forty parasites to a field, have 
been treated. They were injected subcutaneously with 0-3 c.c. of ten per cent, 
solution. At the end of the fifteenth hour no parasites were seen. Treatment was 
o*i to o*3 c.c. of five per cent, solution three times a week for two months. The 
animals all increased in weight. One died sixty-two days after treatment was dis- 
continued. Three rats inoculated with its blood never became infected. The second 
and third pigs were killed at the end of eighty and one hundred days after stopping 
treatment, and the blood used to inoculate controls. No control has shown the 
parasites. Virulent strain. Rhesus. — Weight, 2,8 1 5 grammes. Inoculated Novem- 
ber 16. Blood count : reds, 5,220,000; whites, 1 2,800 ; haemoglobin, seventy-eight 
per cent. On November 3 1 parasites were seen. Two days later, twelve to seventeen 
to a field were noted. The weight was 2,420 grammes. Blood count: reds, 4,600,000; 
whites, 7,200 ; haemoglobin, seventy-three per cent. The parasites counted per 
c.mm. gave 100,000. Oedema of the eyelids and bridge of nose was present. The 
animal was given o - 8 c.c. of ten per cent, solution atoxyl subcutaneously. Four 
hours later : reds, 4,450,000 ; whites, 24,800 ; parasites, 40,000 per c.mm. At the 
eighth hour : reds, 4,740,000 ; whites, 25,200 ; parasites, one to eighty-nine 
fields. Between the fourth and eighth hours the parasites were seen to become 
remarkably degenerated and deformed ; many phagocytes were present. At the 
twenty-fourth hour after injection a count gave reds, 5,050,000 ; whites, 46,000, 
The blood was negative. The leucocytes remained high for a couple of days, and 
then fell ; in none of the phagocytes could any remains of trypanosomes be found. 
Treatment, ro c.c. of ten per cent, solution was given twice a week. The animal 
increased in weight. The autoagglutination of the corpuscles began to be less- 
accentuated, and the number of erythrocytes and the haemoglobin rose. The local 
oedema disappeared. On the thirty-ninth day dysentery appeared, and the animal 
succumbed on the forty-eighth day after injection. The autopsy showed a very 
severe haemorrhagic and necrotic enteritis, with slightly enlarged spleen. Kidneys 
normal. Glands small ; inguinal group haemorrhagic. The blood was non- 
infective in amounts of ro c.c, but infective if fifteen c.c. of pure blood was used. 
Unfortunately, the arsenic was discontinued on the appearance of dysentery. A 
second monkey, inoculated from the first rhesus just before treatment was begun,, 
was treated with the same doses of arsenic ; the parasites disappeared in the same 
way, but the animal quickly succumbed to dysentery. 
Many rabbits inoculated with this strain have been treated. It was found that 
unless treatment was started early that the majority of animals died as it was so 
exceedingly virulent. With these animals treatment was begun earlier and higher 
