160 
REPORT OF TRAVELLING PATHOLOGIST AND PROTOZOOLOGIST 
Appearances 
in the 
fresh blood 
Movements of 
the parasite 
Escape of 
parasite from 
host-cell 
If one examines the fresh hloocl of an infected guinea fowl, elongated spindle-hodies of 
various sizes will he seen. Tu each spindle-body can readily he distinguished the three well- 
known parts characteristic of these parasites. The nucleus of the host-cell is a granular body 
at the middle of the spindle and usually lying at one side, though this is not invariably the 
case, ft is somewhat flattened. Touching the nucleus on one side, and extending beyond 
it towards each end of the spindle, is a large refractile body, more homogeneous than the host¬ 
cell nucleus, but still containing in its substance some highly refractile granules of a greenish 
tint. True brown melanin pigment was never present. This body has been variously described 
as the parasite itself or only the endoplasm of the parasite. The former view we shall find to 
he the correct one. Extending beyond tbe parasite are the drawn-out ends of the spindle. 
This part is much less refractile than the body of the parasite, and does not contain granules. 
The ends may be very much drawn out, so as to resemble fine whip-like organs. The surface 
of the whole spindle-body is differentiated as a fine membrane — the periplast of Dutton, 
Todd and Tobey. This membrane is exactly comparable to the membrane which encloses 
an ordinary red blood-corpuscle, and is to be regarded merely as the differentiated superficial 
layer of the host-cell. As has already been mentioned, in tbe fresh blood it is unusual to find 
any but the spindle shape. In blood taken from a guinea fowl some time dead, or in wet 
films an hour or t^vo old, the spindle shape has frequently been lost and the parasite and 
host-cell have become quite irregular. 
In the fresh-blood preparations, especially if kept at body temperature, the parasites 
within the spindle-hodies are seen to exhibit movements. These consist of slight elevations of 
the surface of the body hardly large enough to be called pseudopodia. In addition, there is a 
second kind of movement in the form of waves of constriction, which commence at the middle 
of the parasite and pass first towards one end and then towards the other end of the spindle. 
Each wave drives the protoplasm of the parasite before it as a fine process into the very tip 
of one end of the spindle. /Vs the protoplasm is passing before the wave into one tip of the 
spindle, behind the wave the protoplasm is flowing out of the opposite tip. The same process 
is repeated in the reverse direction after a few seconds’ rest. It will thus be seen that the 
jjrotoplasm of the parasite is alternately driven into, and withdrawn from, the points of the 
spindle, and it may be that this circumstance has something to do with the peculiar shape 
of the host cell. As the parasite flow's in and out of the spindle ends, it may have the 
effect of producing a to-and-fro movement of the tine whip-like extremities which has some 
superficial resemblance to the movements of a flagellum. This motion, however, on the 
part of the host-cell is quite passive. 
A further point w'hich can be made out from the living specimens is that the spindle-hodies 
are in reality flattened or leaf-like. transverse section through the middle of the spindle 
would not be circular in outline, but oval. Beyond the parasite the drawn-out ends 
of the host-cell are still more flattened, and this point is very suggestive as to the kind 
of cell infected being a flattened cell of the nature of a red blood-corpuscle or one of 
the cells resembling it. 
The movements just described will continue on the slide for three or four hours. In the 
case of the larger parasites — the gametocytes — the host-cell frequently ruptures, and 
eventually the parasite escapes and becomes spherical. This process is exactly comparable to 
the escape of the gametocytes of other intra-corpuscular parasites, such as Ilalteridium, 
Proteosoma or the malarial parasites. After escape slight changes in shape take place for 
some time, and eventually the parasites become quite still and die. In the fresh blood I did 
not see the formation of microgametes nor the “ travelling vermicide ” stage as described 
by Danilewsky and others for similar parasites. However, in the stained films some of 
these forms were discovered. 
