296 Prof. J. E. Salvin Moore and Mr. A. Breinl. [Mar. 9, 
several longitudinal fissions, a certain number of them are seen to become 
shorter, and when subject to the action of Breinl’s stain are relatively blue, in 
contrast to the purple coloration of the remaining parasites (figs. 19, 20, 21, 22). 
In such altered forms it is seen that the extra-nuclear centrosomes become 
related to a protoplasmic elongation, produced perhaps by the rounding up of 
the protoplasm of the animal’s body (figs. 20—22). This elongation becomes 
finally elub-shaped, and the extra-nuclear centrosome, together with the 
flagellum, becomes detached from the rest of the cell, which is now more or 
less round (figs. 21—23). In many cases quite a considerable portion of 
protoplasm is detached along with the extra-nuclear centrosome, and the 
detached structure may present, at first sight, very much the appearance of a 
spermatozoon (figs. 23, 24). 
In some cases it seems that when this process 1s going forward, the extra- 
nuclear centrosome having divided, one half of this structure passes down the 
stalk of the protoplasmic club and enters the rounded mass. In any case, 
however, at the time the extra-nuclear centrosome has become detached, a. 
new centrosome becomes visible in the remaining round cell (figs. 23, 24, 25). 
From this there grows out an exceedingly fine fibre, which is much more 
delicate than the ordinary flagellum (figs. 23, 24, 25). The new extra-nuclear 
centrosome divides, and after a time a second flagellum grows out from the 
second extra-nuclear centrosome contained in the round form (figs. 25, 27). 
One peculiarity in relation to these new flagella is their great length, this 
often being in the proportion of 7: 4 when contrasted with the length of the 
flagellum of an ordinary trypanosome. 
The changes we have just described appear ordinarily to take place before 
the death of rats infected with 7’. equiperdum, but may be encountered also 
at, and for some time after, death, from which facts it might be natural to 
suppose that they are related to the changed condition occurring during the 
approach of death. 
We have, however, found no evidence for this supposition. In none of the 
changes during the production of the round forms or latent bodies is there 
the least suggestion of degeneration. The growth of the new flagella and the 
division of the extra-nuclear centrosomes in the round forms are entirely 
against such a view. This latter conception is confirmed by many experi- 
ments we have made. Thus, if a rat be killed at the time the body derived 
from the extra-nuclear centrosome is passing towards the nucleus in large 
numbers of the trypanosomes, no changes analogous to those we have 
described take place in the blood of the dead animal. We have encountered 
in such cases, as time goes on, nothing but degeneration and disintegration of 
the trypanosomes. Again, in many cases the infection of dourine kills the 
