46 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
4. In most animals the enlargement of the spleen and the presence of 
haemorrhagic glands is a characteristic feature of infection with the 
horse parasite. In the case of the human disease, in the few rats 
that have died infected, the autopsies of these animals have not 
shewn haemorrhagic, nor even markedly enlarged glands.* On 
the other hand, we must remember that we have infected one 
horse with the human parasite, and it has produced a disease in that 
animal clinically indistinguishable from that seen in naturally infected 
horses. We know also that baboons (cynocephalus sphinx) have, up 
to the present, been insusceptible to both parasites. 
5. We have already mentioned that the parasite found in horses, in the 
early stage of the disease, can be distinguished by its morphological 
characteristics from the human trypanosome found in the native. 
The possibility of inoculating some of our animals now immune to the horse 
parasite with the human trypanosome, and other experiments of a like nature already 
in progress, will probably throw considerable light upon what we judge to be the 
most urgent problem requiring solution, namely, the identity or otherwise of these 
two parasites. 
* In the case of a goat and a guinea-pig inoculated with the human parasite, haemorrhagic glands were seen 
at the post-mortem. 
