84 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
monkey is ill it sits on its haunches with its head between its knees ; this position, 
which has been termed the typical sleeping sickness position, is not characteristic of 
trypanosomiasis or ' sleeping sickness ; it is the position assumed by any sick 
monkey from whatever disease it be suffering. We have noted no nervous symptoms 
at all. 
In stained specimens we have not observed any differences between the 
trypanosomes of Uganda and Congo sleeping sickness cases on the one hand and 
Trypanosoma gambiense (Dutton) on the other. In the same species of animals and 
at corresponding stages of the infection the size and appearance of the former 
trypanosomes are precisely the same as those ot the latter as described by Dutton 
and Todd and since observed by us. In rats inoculated either directly or from 
monkeys inoculated directly they present the same stumpy and long forms, the 
former being more numerous in the early stages than in the later. After passage 
through some generations of rats the stumpy forms show the same tendency to 
disappear. In rabbits trypanosomes ot all strains show the same preponderance ot 
short stumpy forms as compared with rats, mice, and guinea-pig, while in guinea-pigs, 
so far as we have yet observed, there is the same greater tendency to length in most 
ot the forms met with. In no animals intected with either the Uganda or Congo 
sleeping sickness trypanosome have we ever seen any form differing in measurements 
or appearance from Trypanosoma gambiense. 
Pathological lesions. — In none ot our animals have we found anything differing 
from the lesions described by Dutton and Todd. Enlargement of the spleen is a 
feature in all the animals, more especially in rats and mice. In a guinea-pig, 
Experiment 133 (Gunjur strain), which died forty-two days after infection, rupture 
of the spleen was found, the rupture extending directly across the organ on its upper 
surface and near the posterior end for about one and a quarter inches. A profuse 
haemorrhage occurred and the animal bled to death. No history of an injury is 
known. Another guinea-pig inoculated with Trypanosoma dimorphum (Dutton and 
Todd) 1 has died from rupture ot the spleen. This case will be published in a forth- 
coming report on Trypanosoma dimorphum. The glands are very little, if at all, enlarged, 
and there are no haemorrhagic glands to be met with as in animals infected with 
Trypanosoma dimorphum. Petechial haemorrhages are rarely seen. In monkeys the 
mesenteric glands are enlarged, but this is without significance, as all our monkeys 
were infected with intestinal parasites. No macroscopical changes in the nervous 
system have been noted. In none of our animals, whether allowed to die or killed 
for special purposes, have we been able to find trypanosomes in the cerebro-spinal 
fluid, although the blood may have contained many trypanosomes, nor have any of 
the animals inoculated with this fluid ever become infected. 
1 I.averan et Mesnil, Compter Rendus de t' 'Academic des Sciences, tome exxxviii, 1904., p. 732. 
