88 
SPOLIA ZEYLANICA. 
bodies in the hanging drop. When kept under observation in 
this condition it has been found by various investigators that the 
development of Trypanosoma ceases even at the blood-tempera¬ 
ture,* and sooner or later the parasite becomes completely 
dissolved. 
So it happens with the free hsemogregarines of H. mirabilis. 
Several hanging drops were prepared towards six o’clock in the 
evening. On the following morning not a trace of the parasites 
was to be found beyond here and there some questionable granular 
matter. The blood-corpuscles remained perfectly normal. As 
mentioned above, the endoglobular parasite undergoes no such 
rapid dissolution, but persists as long as the corpuscle which 
harbours it. 
The movements of our free hsemogregarine consist of gliding 
slowly along and turning, sometimes bending double upon itself. 
Then again an individual will appear fixed at one spot by its 
more attenuated hinder end and will revolve by a rather slow 
screw-like motion like the spores of Sarcocystis. Then will appear 
a very rapid whirling of the body displacing the neighbouring 
corpuscles. This last movement, as later observations on stained 
preparations showed, was probably due to the efforts of the parasite 
to free itself from the corpuscle. 
The most remarkable and as we believe hitherto undescribed 
fact in connection with these parasites relates to their origin 
within the blood corpuscle. This is shown in our preparations 
(stained by Romanowsky’s method) in the clearest manner. 
Many of the corpuscles contain parasites of relatively large size 
and lightly crescentic or reniform in shape consisting of a delicate 
membrane, closely applied to which are more or less distinct 
rows of red-stained granules uniformly distributed. The centre 
of this body, along its entire length, is occupied by a pale blue- 
stained body containing a well-defined densely staining nucleus. 
The enveloping body is the mother-cell of the contained body and 
in the following description we will refer to it as the cytocyst. 
The single organism which the cytocyst produces escapes from 
the membrane and from the corpuscle, and becomes the freely 
motile parasite described above from life. We will call it a 
monozoite , and the cytocyst is a monozoic cytocyst. 
The nucleus of the monozoite lies behind the centre of the body 
both before and after its birth. Our preparations show all stages 
of emergence of the monozoite. When fully formed within the 
cytocyst, the hinder end of the monozoite is slightly bent, 
indicating that a certain pressure is exerted on the cytocyst, 
* Cf. v. Wasielewski and Senn., op. cit., p. 45]. See also above p. 82. 
