E. Hindle 
431 
development of the “black line” in T. gavibiense. In this latter try¬ 
panosome, however, it is also possible to trace the passage of chromatin 
from the kineto-nucleus to the region of the tropho-nucleus (figs. 2, 6, 40), 
and it is rather difficult to understand why T. gambiense should require 
two methods of transferring chromatin from one nucleus to the other. 
The nature of these granules is rather problematical, for although 
the percentage of trypanosomes containing them rose from 30 “/o, before 
treatment, to 60 % two hours after, yet this difference is not sufficiently 
well-marked to warrant the assumption that they are merely degeneration 
products. 
As a rule these granules (or chromatic bodies) seem to be derived 
from the kineto-nucleus by means of an aberrant division, after which 
one of the daughter nuclei passes forward towards the tropho-nucleus 
without developing a flagellum. On its way it often divides (figs. 2, 6, 
38), and these two granules pei’sist for a long time in the region of the 
tropho-nucleus finally, however, dissolving in the cytoplasm. Occasion¬ 
ally a succession of these bodies is given off from the kineto-nucleus 
and forms a longitudinal row extending down the middle of the cell. 
The degeneration of the axial filament and its associated structures 
is best considered at this point, together with the granules arising from 
them. 
The kineto-vacuole, when present, begins to enlarge shortly after 
treatment, and in advanced stages of degeneration may become as large 
as the tropho-nucleus (figs. 40—52). Under certain conditions the 
vacuole becomes filled with chromatic substance, probably derived from 
the kineto-nucleus, and is then a very conspicuous feature of the cell 
(fig. 12). 
As the axial filament degenerates it usually becomes cln’omatic 
(figs. 7—10), and then breaks up into a series of granules (figs. 8, 33) 
arranged in a longitudinal row. 
Occasionally chromatic substance from the kineto-nucleus seems to 
flow round the kineto-vacuole and along the axial filament, which then 
stains black with iron haematoxylin. The passage of this densely 
chromatic substance along the achromatic axial filament gives the 
appearance of a black line growing down the middle of the cell, and 
Salvin-Moore and Breinl (1907) regarded it as being of considerable 
importance in the life-cycle of T. gambieiise. They suppose that this 
“black line” formation represents a kind of autogamy, and figure stages 
shewing the growth of the black line from the kineto-nucleus to the 
region of the tropho-nucleus. But it will be seen from figs. 14, 15 that 
