i + THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
a series of animals have been inoculated. The incubation period and duration of the 
disease is much less than with the ordinary strain of parasite. One of the guinea- 
pigs has since shown parasites in its blood. Whether the parasite from this guinea-pig 
is as virulent as that from the rabbit is not as yet determined. The animals died four- 
and-a-quarter weeks after the appearance of parasites, there being over one hundred 
to a held at death. Further experiments in progress. 
Experiment No. 890. Inoculated intraperitoneally with 9-0 c.c. pure blood from 
rabbit 877. Mixture contained one parasite to a field. This rabbit was inoculated in 
the third passage from rabbit 823 (see above). On the tenth day the temperature 
rose to I03 - 4°F. No parasites were seen. Two days later a trypanosome was 
discovered. From that time until the baboon's death on the forty-first day the 
organisms were present at nearly every examination. Death took place suddenly. 
A pup inoculated with heart blood from this baboon developed the disease after a 
prolonged incubation, the parasites were present in only very small numbers up to its 
death. 
All three baboons showed a rise of temperature to I03°-I04° F., and following 
on this an irregular temperature which persisted, usually becoming lower and often 
being sub-normal before death. Parasites were found in the blood of only two of the 
baboons despite repeated centrifuging of the blood, but though the parasites were 
hardly ever present, and then only one to two to a cover, still animals inoculated with 
large amounts of their blood have developed the disease. Foss of weight and anaemia, 
though gradual, was present in all three cases. The autopsies, especially of 747 and 
709, showed an enlarged and firm spleen, slight enlargement of the lymphatic glands. 
Dr. Brrinl has included the brains, cords, and organs of these animals in his report 
on the histo-pathology. 
The strain derived from baboon 747 and passed through rabbit 823 has been 
inoculated into a great number of animals. In all the incubation period has been 
greatly shortened. Rabbits very often show parasites in their blood in two to four- 
and-a-half days, and death may occur as early as the fifth to eleventh days after 
inoculation. In many cases the parasites augment from day to day until there will be 
one hundred and fifty to two hundred or more to a field. The animal will very often 
suddenly die. The number of trypanosomes will frequently decrease, they usually 
commence to increase in numbers again in three to eight days, and continue to do so 
until the blood actually swarms. A very severe anaemia occurs, loss of weight is 
marked. Coma may develop a few hours before death or the animal may die while in 
the act of eating and apparently quite strong. The temperature is usually very high, 
the incubation rise being often to i04°-ro6° F. It usually continues high, hardly 
falling at all in the acute fatal cases. The post-mortem of these acute cases shows a 
multitude of parasites in every organ and in the blood and serous exudates, acute 
swelling of the spleen, enlargement of the glands — some of these may be haemorrhagic. 
