33 2 
generally easily appreciable, at least in the blood, but as 
we shall see later, such forms have also been described 
in the gut of flies transmitting particular trypano¬ 
somes, and the differences are there said to be well 
marked. In the case of F. brucei , for example, three 
types are described in the blood. 
(1) Male Forms .—Excessively slender forms 
staining deep blue, with a sharply defined, rather long 
chromatin-rich nucleus. They are more actively 
motile than other forms. 
(2) Female Forms. —Flagellum short. Membrane 
slender, little folded ; two or three times as broad 
as other forms. They stain a light blue ; have few 
or no granules and the nucleus is spherical. 
(3) Indifferent Forms. —The most numerous form. 
The nucleus is not sharply defined, and the protoplasm 
contains numerous granules. 
It must, however, be remembered that all transi¬ 
tions appear to occur between these forms, and that 
observers are by no means agreed as to which of these 
forms are which ; and finally it must be noted that the 
amount of granules and the depth of staining of the 
protoplasm of a trypanosome can be made to change 
at will by varying the composition of the Romanowsky 
and by washing for variable lengths of time. 
Mode of Division. —This is by longitudinal division. 
The trypanosome at the time of division increases 
considerably in thickness. The nucleus and blepharo- 
plast divide, sometimes one first, sometimes the 
other. A new flagellum is formed by an out-growth 
from the new blepharoplast; or according to others 
by a splitting of the base of the old flagellum. Finally 
the protoplasm also divides. For rosette formation 
vide under F. lewisi. 
Encysted Forms. —In animals treated with atoxyl 
