1908.] 



A Trypanosome from Zanzibar. 



29 



irregular-shaped granules and masses of chromatin-staining material. There 

 are also present numerous well-marked vacuoles of various sizes, which are 

 unstained, and, as mentioned above, highly refractile. 



Nucleus. — The nuclei are of every form and shape, and often broken up into 

 irregular masses. 



Micro-nucleus. — The micro-nuclei are irregularly placed ; in some cells are 

 not easily distinguishable from other granules contained in the protoplasm, 

 but in many are clearly seen as deeply-staining bodies, round or rod-shaped, 

 in close connection with the point of origin of the flagella. 



Flagellum. — The flagella are, as a rule, thick and fleshy. In the irregular 

 forms they appear to spring from any part of the shapeless mass of proto- 

 plasm, and in any direction. 



Undulating Membrane. — The undulating membrane is also characterised 

 by its extreme irregularity. In many cells it appears to be absent, while in 

 others it is well marked, broad, and thrown into folds. 



Colonies or Aggregations. — The individual trypanosomes which go to compose 

 the large aggregations are as a rule short and stumpy in form, with oval- 

 shaped nucleus and short stumpy flagellum. They are of irregular shape 

 and size, and are placed without any seeming order. 



Cultural Characters of Trypanosoma dimorphon (Dutton and Todd). 



It is unnecessary to describe in detail the cultural characters of this, 

 trypanosome, as they agree exactly with those of Dr. Edington's. 



Cultural Characters of Trypanosoma congolense (Broden). 



Several attempts were made to cultivate Trypanosoma congolense, but 

 none of them were very successful. There is certainly not the rapid growth 

 of this trypanosome which distinguishes Dr. Edington's trypanosome and 

 Trypanosoma dimorphon. It is only after a long search that individual 

 trypanosomes can be found in the preparations. There is no formation of 

 masses or aggregations filling several fields of the microscope as in the others. 

 It is difficult to say whether there is any real multiplication or not. All that 

 can be said is that, for about eight days, living trypanosomes can be seen. At 

 first these are shaped like the ordinary trypanosomes found in the blood, only 

 larger and swollen in appearance ; but by the fifth and following days these 

 change into most irregular and fantastic shapes. Nothing living could be 

 seen after the eighth day. This cultivation experiment would therefore seem 

 to strengthen Dr. Laveran's opinion that Trypanosoma dimorphon and 

 Trypanosoma congolense are distinct species. 



