THE TRYPANOSOMA BRUCII. 467 



between tliem ; and we are, moreover, very doubtful 

 whether the dots in these orgauisnis are really chromatin, 

 as we have stated when describiug them, since they stain 

 a much darker colour. The probability seems to be that 

 they are not. We are now of opinion that the following 

 would be the more probable sequence of the life-history 

 of the Trypanosoma Brucii. 



1. Longitudinal division, which is very common, and can 

 be seen more or less in the blood of all the animals we have 

 used. 



2. Coujngation, the essential of which is the fusion of 

 the micronuclei of the conjugating pair of oi-gauisms. 

 After this process the organisms probably separate and 

 go on as before, probably with renewed enei'gies. This 

 is known to be the case in some nearly allied organisms. 



•3. We are here inclined to place tentatively the fusion 

 of the adult forms. This process begins by the formation 

 of tangles, and the organisms then lose their individual 

 forms, and fuse into a more or less homogeneous mass, 

 which under the best optical conditions appears to be an 

 irregular aggregation of protoplasm containing many micro- 

 and macro-nuclei. 



These latter divide again and again, so that the mass 

 seems to consist of little else but micro- and macro-nuclei; 

 then Hagellated amoeboid forms are given off from the 

 margin, and these grow and eventually lengthen out into 

 the adult organism. There is a tendency for these masses 

 to be formed in certain structures only : in the rat, mouse, 

 cat, and dog they are found in the spleen, and in the blood 

 just before death. They are also found in the blood from 

 the lungs, in the lymphatics of the eyes and genitals^ and 

 in the cerebral capillaries. 



A point in favour of the above opinion is the fact ihat 

 in animals from which the spleen has been previously 

 removed, these masses are found in all stages of formation 

 in the blood diiring life, and before the animal has begun 

 to get apparently ill; the spleen being removed, in which 



