66 The Genus Leucocytozoon 
round the nucleus of host-cell which is found at the middle of the 
spindle. 
4. Three forms of parasite can generally be recognised in the 
peripheral blood,—large deeply staining parasites which are the female 
gametocytes, pale staining parasites which are male gametocytes and 
lastly young forms which are possibly immature gametocytes. 
5. The male gametocyte develops into a Polymitus or in other 
words it forms male gametes which are narrow whip-like organisms 
resembling the male gametes of the malarial parasites. These male 
gametes fertilize the female gamete and a motile zygote results. 
6. The nucleus resembles that of Halteridium. The male nucleus 
consists of chromatin granules scattered about the centre of the parasite. 
The female nucleus is a more compact group of chromatin granules in 
the midst of which or to one side is a granule 1 definitely marked off 
from the rest by its larger size. It is possible that this granule is a 
karyosome. 
1 There is a tendency for those who wish to establish the trypanosome nature of the 
intracorpuseular blood parasites, to describe any granule of chromatin which is larger 
than those of the main nuclear mass as homologous with the smaller chromatin body of 
trypanosomes. It must be remembered that extranuclear chromatin is of common occur¬ 
rence in Protozoa so that it is exceedingly misleading to homologise any such granule of 
an intracorpuseular parasite with the definite micronucleus of trypanosomes. Woodcock 
has considered that his discovery of such a granule in Halteridium is the first definite 
evidence which has been brought forward in support of Schaudinn’s contention that 
Halteridium has a trypanosome stage in its life history. It appears to me that Woodcock 
has failed to prove the one point necessary to support this hypothesis. It is not so much 
the discovery of such a granule that is required but the conclusive evidence that this 
granule is homologous with the micronucleus of a trypanosome. This evidence Woodcock 
has failed to produce. As a matter of fact similar granules had been described by several 
observers before Woodcock’s discovery. In the Third Report of the Wellcome Research 
Laboratories, Khartoum, I have described this granule in the Leucocytozoon of the guinea- 
fowl and have figured it in the Halteridium on Plate XIII and again in the Haemo- 
cystidium on Plate XIV. It is equally undesirable to consider the similar granule 
in the piroplasmata as a micronueleus till it has definitely been proved to give rise 
to a flagellum or to have originally done so. In the case of the piroplasmata such 
a view has already produced considerable confusion with the Leishman-Donovan bodies. 
I quite agree with Calkins (Chap. IX, p. 269) who says in reference to the present 
tendency to group the Haemosporidia with the Mastigophora, “It is possible that 
future research will justify this step and that the large, relatively immobile blood 
parasites like Lankesterella of the frog, haemogregarines of turtles and tortoises, Karyo- 
lysus of lizards, haemoproteus of birds and plasmodium of man are like the Leishman- 
Donovan bodies only passing phases of some flagellated protozoon, but at the present time 
the evidence is not weighty enough to warrant such a step even as a working hypothesis. 
The weakness of the evidence, apparent as soon as reviewed may be briefly summarised as 
follows, etc.,” and again on p. 270. “For these reasons, therefore, I believe it premature 
to separate the haemosporidia from the sporozoa. ” 
