On the Organism found in the Tsetse Fly Disease. 277 



in twenty-four hours after inoculation. We have not found that 

 generalisation of the organism in the lymphatic glands occurs until 

 nearly the end of the disease, when the organism is present in very 

 large numbers in the blood. In the rabbit, in which the organisms are 

 few or rare in the blood, the glands do not show any marked change, 

 and the Trypanosoma are not readily found in them. Many other 

 forms are found in the glands, to which reference will be made 

 below. 



(c) In the Spleen, — The adult Trypanosoma is found in but small 

 numbers in the spleens of the various animals we have examined ; but 

 other forms are found there which will be described later. The en- 

 largement of the spleen is post mortem the most obvious fact in the 

 morbid anatomy of the disease ; it may attain even to four or five times 

 the average volume — this is especially the case in the rat. 



(d) In the Bone-marrow. — We have found either very few flagellate 

 organisms or none at all, in the bone-marrow of the various animals we 

 have worked with. The marrow is altered in colour and structure, 

 but there does not seem to be a greater number of Trypanosoma than 

 can be accounted for by the blood in the marrow. 



In the other organs and parts the number of organisms present 

 depends upon the relative quantity of blood in the part. 



2. In the Body of Spleenless A nimals. — As the spleen in the ordinary 

 animals is the organ which is most obviously altered in this disease, 

 we have made a series of inoculations into animals (dog, cat, and 

 rabbit) from which the spleen had been removed a year ago. In the 

 dog, the adult forms of the Trypanosoma are not found so early in the 

 blood of spleenless as in that of ordinary animals (seventh day as com- 

 pared with fourth day after inoculation). The glands, after death, 

 are much more generally enlarged, and are reddish in colour, and con- 

 tain many more organisms than in the normal animal. Both the blood 

 and glands contain, however, numerous other forms to be described 

 below. 



This marked difference in the colour of the glands of spleenless 

 animals is probably clue to the removal of the spleen, and the glands 

 consequently taking on some of the splenic functions. 



The bone-marrow is much altered, and in it likewise are found a 

 large number of Trypanosoma : both flagellate and what are termed 

 below "amoeboid" forms. 



In the cat the conditions of experiment were altered, the blood (1 c.c.) 

 from the infected animal being introduced, with every precaution to 

 avoid contamination of the tissues, direct into the jugular vein. In 

 this case the organism appeared in the blood in numbers on the fourth 

 day, and the animal died on the twelfth day. As the Trypanosoma 

 were introduced into the blood stream direct, there was no marked 

 glandular enlargement, but the glands were all reddish in colour, the 



