1908.] 



A Trypanosome from Zanzibar. 



25 



At times the number of these globules is increased, as when the culture is 

 kept at 34° C. The presence of numerous large, highly-refractile globules 

 in the cultural forms of Trypanosoma Irucei is attributed by Novy and 

 MaaNeal to degeneration of the organisms, owing to imperfection of the 

 culture medium. These globules become more numerous as the age of the 

 culture advances. Do not seem to alter in position or shape if kept under 

 observation for several hours. Eesist staining completely. Laveran and 

 Mesnil suggest that the globules are of the same nature as the refringent, 

 unstainable granules found in Trypanosoma rotatorium. 



Undulating Membrane. — No detailed description available. 



Flagellum. — The flagellum in the living cell is by no means as distinct and 

 as long as that of Trypanosoma leuisi. 



Motion. — The motion of Trypanosoma irucei is slow and wriggling, and 

 only exceptionally is a slowly-progressive form observed. The wave-motion 

 slowly passes along the thick, undulating membrane, and gives the appearance 

 of a spiral rotation to the entire cell. Scarcely departs from its place (Novy). 

 In a young culture the trypanosomes are found to possess very active 

 movements. Sometimes they advance across the field moderately quickly, 

 but their rate of movement is always much slower than that o"f the rat 

 trypanosomes, whose flagella are longer and more rapid in motion (Smedley). 



Colonies or Aggregates. — Occurs in groups or rosettes. Barely forms masses 

 of more than 10 to 20 cells. The individuals are long, narrow, and show the 

 peculiar writhing motion. The flagella are directed outwards, and the appear- 

 ance of the whole may be compared to the snakes on a Medusa head. The 

 stellate group with the bright, refracting globules within the cells, suggests 

 a jeweller's " sun burst " (Novy). The active movements of the trypano- 

 somes, and the large glistening vacuoles with which they are studded, give 

 these colonies a singularly beautiful appearance (Smedley). 



B. Fixed, stained. 



Protoplasm. — The protoplasm invariably contains a few deeply-stained 

 granules of a red or violet colour. The vacuoles are seen as clear circular 

 spaces with sharply-defined outlines in stained preparations (Smedley). 



Nucleus. — Eound or oval in shape ; and in older forms it breaks into masses 

 of cromatin, which are found distributed through the protoplasm of the cell 

 (Smedley). 



Micro-nucleus. — This is much smaller than in Trypanosoma lewisi ; it is 

 usually circular, but sometimes elongated. It stains a deep red or purple 

 colour, and it is sometimes difficult to distinguish it from the other granules. 



