KEl’OKT OF TKAVKIiLINU PATHOLOGIST AND PHOTOZOOLOGIST 
151 
Watched for a long time the parasites exhibited no movements except a slight change in 
position of the pigment grains. Neither addition of citrate solution nor any other reagent 
brought about any changes comparable to the microgamete formation known to occur in other 
intra-corpuscular pigmented parasites. Jllood taken from the snake some twelve or twenty 
hours after death revealed many spherical parasites free in the plasma. Whether this is to be 
explained as a process of development or merely as a dissolution of the red cells liberating the 
parasite cannot be stated. 
In the films stained by Giemsa stain the appearances are much the same as have been 
described for the two species of Ilcemocystidium already known. Ilcmiocystklium from the 
Indian river tortoise {Chitra indica) was described by Simond. and from the tree-dwelling 
gecko {llcemidactylus leschcnaultii) by Castellani and Willey. The name Ilcemocystidium 
was created by these latter observers, for the parasites, owing to certain differences in their 
morphology from other intra-corpuscular parasites. A parasite similar to these has been 
described by Laveran from Testudo pardalis of South Africa. As in the case of Ilalteridium 
there are male and female gametocytes, and an absence of schizont forms. The gametocytes 
differ in size and shape from those of Ilalteridium, but this is insufficient ground on which to 
base a new genus. The fact that the parasite occurs in a cold-blooded host instead of a warm¬ 
blooded one is also a non-generic character. In the cases of such parasites it is necessary to 
know something more of the life-histories before it can be definitely stated that they belong 
to a distinct genus. However, till something more is known of their life-histories, the name 
IIcemocystidiunL may provisionally be accepted for these parasites till further observation 
confirms or contradicts this. 
On Plate XIV. the parasites are shown as they occur in films stained by Giemsa stain. 
The full-grown parasite is a large liody of oval outline containing at its centre a nucleus of 
chromatin granules, and scattered about its substance coarse grains of pigment. As in other 
species of Hcemocystidium, the full-grown parasites may be differentiated into male and female 
gametocytes according as the protoplasm is dense or otherwise. Female gametocytes are 
figured in Plate XIV., figs. 7, 12. They stain a deep Idue and have a nucleus at the centre 
consisting of granules of chromatin, one of which is differentiated as a karyosome. The 
pigment as coarse granules is either uniformly scattered through the cell, arranged in irregular 
clumps, or grouped at either end of the parasite, as is frequently seen in Ilalteridium. The 
male gametocytes are pale pink staining bodies. The chromatin of the nucleus may he central, 
as in the female gametocyte, or more scattered (Plate XIV., figs. 3, 8). The disposition of 
the pigment is the same as in the female forms. The gametocytes, when full growm, measure 
about 21,i( by 14|U. In the blood taken from the snake some hours after death, extra-corpuscular 
forms are met with. A female gametocyte in this stage is figured in Plate XIV., fig. 5. Such forms 
show some resemblance to the female gametocyte of the quartan variety of malaria. At 
fig. 6 is a male gametocyte which has become spherical and has several chromatin 
granules. This shows some likeness to the early stages of microgamete formation in 
other similar parasites. In fig. 11 is a cell completely filled by a male and female 
gametocyte, while double infection of a cell with this parasite and the hsemogregarine is 
illustrated in figs. 8 and 12. 
The youngest forms of parasite met with are small masses of protoplasm with a single 
chromatin dot. Slightly more advanced forms show pigment in the form of a coarse granule 
and also frequently a vacuole (Plate XIV., figs. 2,10,15, 16). No forms were seen which could 
definitely be described as schizonts, though the presence of the young forms demonstrates that 
some form of multiplication must he taking place. Examination of the internal organs was 
fruitless in revealing what this multiplication was. 
Appearances 
in the fresh 
blood 
Appearances 
in the stained 
blood 
Gametocytes 
No schizonts 
observed 
