447 
the nature of an accident than a necessary process involved in the 
normal life cycle of the parasites. Some such conclusion is borne out 
by other facts in relation to trypanosome infection. Thus in the case 
of Dourine,* simple inoculation of blood will transmit the disease, but 
it is habitually communicated amongst horses in quite a different 
manner, namely by coitus. Consequently, if there is a sexual stage 
in the life history of Trypanosoma equiperdum, this sexual stage must 
occur normally in the body of the horse. Further strains of trypano¬ 
somes, such as those of sleeping sickness and Dourine , may be kept for 
years in our laboratories through inoculation from animal to animal. 
In fact, such strains may be continued in this way for a quite 
indefinite period, a process involving an endless number of 
generations in the blood, and it consequently follows that if in such 
forms the sexual stage occurs only in some other host, this phase can 
be dispensed with for an altogether indefinite period. 
As a matter of fact, there are yet other observations bearing upon 
Schaudinn’s researches, which if they do not necessarily render his 
account of the sexual act improbable, seem to clearly indicate that it 
may exist in the instance of T rypanosoma nod nee as a very unusual 
exception, an exception which may be incapable of throwing any 
general light upon the life history of the great group of organisms to 
which Trypanosoma nocture belongs. We may refer also particularly 
to the author’s account of what he regards as the reduction process. 
This, according to Schaudinn.t amounts to a sexual determination, 
or differentiation, accomplished through a nuclear division. That is 
to say, there occurs in T rypanosoma noctuce a division (heteropolar 
mitosis, Schaudinn), which separates the female moiety of an 
hermaphrodite nucleus from the male. In other words, Schaudinn 
resuscitates (although he does not appear to allude to this fact) 
Balfour’s and Minot’s view of the formation of the polar bodies, and 
the extrusion of the so-called residual corpuscle during the iormation 
of the spermatozoa. 
* Rabinowitsch and Kempner. Centralblat fur Bakt. Bd. xxxx l J 7 ’ m o6 
See also Minchin, Gray and Tulloch. Pro. Roy. Soc., London. \oI. 7 » 9 • 
See further Laveran and Mesnil. Trypanosomes et trypanosomia,es. a , 
1904. 
+ Schaudinn: Neuere Forschungen fiber die Befruehtung bei 
erhandlungen der deutschen zoologischen Gesellschaft auf de - • J 
sammlung. Leipzig, 1905. 
