PIROPLASMA MURIS. 499 



(fig. 17), while a distinct vacuole, more or less polar in 

 position, may occur in other forms (figs. 1, 2, and 5). 



The outer border of some of the larger forms of the 

 parasite often takes up the stain more intensely than the 

 more central cytoplasm, and so appears of a distinctly blue 

 tint after Romanowsky staining. 



Usually there is only one chromatic dot in each ovoid, 

 pyriform, or amoeboid body (figs. 2, 3, and 1 7) . Occasionally 

 two chromatic dots are seen (figs. 4 and 15, note also fig. 18), 

 while in one case, as already mentioned, there was a chromatic 

 appendage, somewhat flagellum-like, protruding from the 

 body of the parasite, and even outside the erythrocyte host 

 (fig. 19). The chromatin body averages 0"3 jw to O'b f.i in 

 diameter, and may be irregular in outline. 



A few remarks seem necessary respecting the chromatin 

 of the trophozoites of P. muris and other Piroplasmata. In 

 view of the recent researches of Schaudinn and others on 

 the " vegetative " and " reproductive " differentiations of the 

 chromatin in parasitic Protozoa one may well hesitate 

 nowadays to use indiscriminately the terms " nucleus " and 

 ''karyosome."^ Laveran (24), in 1901, used the term 

 " karyosome " to designate the chromatic body of the tro- 

 phozoite of P. equi. However, since all the species of 

 Piroplasma are comparatively small, it is difficult, in the 

 pi'esent state of our knowledge, to be quite precise in naming 

 the chromatin body or dot occurring in a trophozoite of 

 Piroplasma, and it would seem best simply to refer to such 

 structures as ''chromatin bodies " or "chromatic dots." 



No bacillary (25) or rod-like forms were seen, types which 

 are characteristic of P. bigeminum in the blood of immune 

 Bovines (48), and are also common in the case of P. parvum 

 (48, 49). 



The mode of multiplication^ of the trophozoite is, as 



1 Siedlecki has lately (Oct., '05) written on the " Significance of the 

 Karyosome," putting forward somewhat different views ('Bull. Acad. So. 

 Cracovie,' 1905, No. 8, pp. 559-81). 



■^ This mode of multiplication, which is endogenous, is in this genus simple. 



