280 Mr. EL G. Plimmer and Prof. J. Eose Bradford. 



D. Life-History of the Trypanosoma " Bmcii." 



Besides the forms mentioned above, we have seen in the blood and 

 in the organs divisions of the adult form, both longitudinal and trans- 

 verse, the former the more frequent ; but we think that this direct 

 mode of reproduction is far less common than the indirect by means 

 of conjugation (probably), breaking up of chromatin, production of 

 amoeboid forms, with subsequent division of these amoeboid forms, and 

 the formation of plasmodia by the aggregation or fusion of the 

 amoeboid forms, and these finally giving off flagellate forms, at first 

 small, and gradually increasing up to the normal adult form. 



So that we should tentatively summarise the life-history of the 

 Trypanosoma found in Tsetse Fly disease, which we think might properly 

 be called " Trypanosoma Brucii" in recognition of the work done in 

 connection with it by its discoverer Major Bruce, F.R.S., as follows : — 



1. Reproduction by division, this being of two kinds : — 



(a) Longitudinal, the commoner. 



(b) Transverse, less frequent. 



2. Conjugation, consisting essentially, so far as our observations go, 

 of fusion of the micronuclei of the conjugating organisms. 



(a) After this we are inclined to place those forms mentioned above, 

 in which the chromatin is broken up, and scattered more or less uni- 

 formly through the whole body of the Trypanosoma, since this occurs 

 after conjugation in other organisms not far removed biologically from 

 this one. The next stage in our opinion is the amoeboid ; we think 

 that the flagellate form becomes amoeboid perhaps after conjugation, 

 but also probably apart from this process. 



(b) Amoeboid forms. These are found with and without flagella, of 

 various shapes and sizes, but always possessing a macro- and micro- 

 nucleus. These forms are constantly seen in the process of division, 

 and sometimes are very irregular in shape, with, in this case, an 

 unequal number of macro- and micro-nuclei, the latter being the more 

 abundant. The amoeboid forms then fuse, or aggregate, together to 

 form — 



(c) The plasmodial forms. Whether these are true plasmodia, or 

 whether they are only aggregations of amoeboid forms it is not yet 

 possible to say, but as many related organisms form true plasmodia 

 we are inclined to look upon these masses, provisionally, as true plas 

 modia. In the spleen these plasmodia reach a large size. From these 

 again are given off' — 



(d) Flagellate forms, which increase in size, and become the ordinary 

 adult form. Small flagellate forms are not infrequently seen in pro- 

 cess of separation from the margin of these plasmodial masses. 



Besides these forms we have observed frequently, especially in rat's 



