484 



TELOSPORIDIA 



itself on one side of the cyst-wall while the nucleus comes more into the middle 

 The cyst becomes more swollen and rounder, and is most difficult to stain, 

 being brilhantly clear and refractile, but as it grows older it becomes filled with 

 round or oval, clear, refractile granules of large size. No details are given of the 

 action of the nucleus or of the cytoplasm during the stages, which, of course, 

 marks a gap in the life-history. As the cyst matures the granules become less 

 in number, and merozoites are seen lying among them, and, later, the granules 

 having disappeared, only merozoites, which number about thirty, are seen 

 lying, along with a little granular matter, in the oval or circular cyst, which 

 may Tdc 48 in diameter. 



Fig. 156. — Diagram of the Life-Cycle of Hcsmogregarina canis James. 

 (Constructed from drawings by Christophers.) 



It does not appear clear what happens to these merozoites, but from Christo- 

 phers' description one is led to infer that they infect other cells in the bone- 

 marrow of the dog, and thus become young trophozoites. 



Trophozoite. — By inference one is led to beheve that the trophozoite 

 probably appears in the bone-marrow as a small, round, or egg-shaped body, 

 possessing no capsule, and having a chromatin mass of isolated, rod-shaped 

 granules arranged loosely in a circle. These trophozoites he in a mono- 

 nuclear cell, which are the parents of the transitional cells, which are looked 

 upon as the parents of the polymorphonuclear leucocytes, but when infected 

 by the parasite the proper development is not completed, and hence the 

 appearance in the peripheral blood of a peculiar tyi^Q of cell containing the 

 encapsuled parasite. The young trophozoite is seen in the liver and spleen as 

 well as in the bone-marrow, but is rare in the peripheral blood. This tropho- 



