Notes on certain Blood- Inhabiting Protozoa. 233 



of this parasite in the blood of the vertebrate host. I have 

 been able to corroborate a number of the results arrived at 

 by the above-mentioned observer. My material, however, 

 showed certain points of interest which are worthy of 

 description. 



The infection with which I was working was one of long- 

 standing. Two out of the three cases which came under my 

 observation were very severe, an enormous number of para- 

 sites being present in the blood. The host was in each case 

 a guinea-pig. 



Division. This process agrees essentially with that 

 described by Prowazek (Studien iiber Sdugetiertrypanosomen, 

 Arh. aus dem kaiserh. Gesund., Bd. xxii. Heft 2), but 

 there appears to be a certain amount of variation in 

 detail. Prowazek describes a division of eight chromosomes 

 in the somatic nucleus, which become grouped finally at 

 either end of the dividing karyosome, without forming an 

 equatorial plate. The division of the nucleus is preceded 

 by the division of the blepharoplast. Division, as I observed 

 it, agrees broadly with this description, but both the karyo- 

 some and the chromatin show some points of difference. 

 Thus the karyosome, which is on the whole a larger and 

 more prominent structure than is indicated by Prowazek's 

 figures, shows a very strong tendency to precocious division. 

 Quite a common nuclear condition is shown in Fig. 1, where 

 the karyosome is already divided, and where the chromatic 

 network has broken up into separate chromosomes, which lie 

 arranged in a comparatively regular oval. More often the 

 chromatin becomes closely grouped in irregular masses round 

 each karyosome (Pigs. 1, 2). 



Forms strongly suggesting autosynthesis of the nucleus 

 were not infrequently met with (Fig. 4) ; this process involves 

 one or more, usually two, divisions of the karyosome. Of the 

 four karyosomes thus produced, two apparently fuse together, 

 while the other two degenerate. 



Parthenogenesis was not observed, although the nucleus 

 was not infrequently found with a divided karyosome, and 

 the chromatin arranged in four or more bars running across 

 cit right angles to the main axis of the nucleus. This, 



