463 
divides normally, and that it is the half so produced which enters into 
connection with the nucleus during the formation of the black line. 
In this case, it may be that the nucleus receives once more a 
morphologically complete extra-nuclear centrosome produced in the 
ordinary way by division. Our observations are not conclusive with 
regard to these matters. 
Considering the whole question from another point of view, it 
should be remembered that it is only among a percentage of the 
trypanosomes present during the periods of the maximum numbers of 
the parasites in the blood which can be lounrl at any time to exhibit 
the formation of the black line, and we have to assume either that all 
the trypanosomes which ultimately form the latent bodies have 
passed through this metamorphosis, or that only some of them have 
done so. 
We have no conclusive evidence upon this question. If, however, 
it should eventually be shown that only a fraction of the latent bodies 
are produced from trypanosomes which have passed through the 
black line metamorphosis, then it will become clear that there are 
two series of latent bodies, one class produced after the black line 
formation, and the other without this taking place. Should this be 
the case, the suggestion that the black line metamorphosis represents 
a peculiar form of the sexual act, or conjugation, which we have merely 
provisionally considered, will be found probably to be inaccurate. 
There will be an actual dimorphism among the latent bodies, and it 
will in this case be strongly suggested that the actual sexual act has 
yet to be discovered, and has been overlooked. We think it would 
be unprofitable to pursue this question further in the present Memoir. 
It is obviously a question that can only be properly considered after 
the phases of the life cycles of other trypanosomes are available. 
In the introductory portion of this paper it was pointed out that 
there exists a complete discrepancy between “ reduction as 
apparently understood by Schaudinn* and reduction as understood 
by biologists in general. Without throwing any reflection whatever 
upon the correctness of Schaudinn’s observations in relation to the 
phenomena exhibited in the life cycle of Trypanosoma noctua , it is 
dear that, whether the process he describes exists or not, this process 
Loc. cit. 
