THE LEUCOCYTOZOA 



251 



broad compared with their length, and may be accurately 

 described as bean-shaped or reniform (figs, i, a-d ; 3, b, c). The 

 average size of the intra-corpuscular (cytozoic) forms is from 

 8 ft to io'5 fju long and 4/5 /i, to 5*5 /u, broad. 



Sometimes it is necessary for the Lcucocytozoa to leave the 

 leucocyte or host cell and come out into the plasma, and so- 

 free forms are found. The parasites that are free in the plasma 



Fig. 1. — Various Leucocytozoa. 



A, L. cam's (after James), in polymorphonuclear leucocyte, parasite lying to the left, b, L. funambuli 

 (after Patton), showing the splitting of the nucleus of the host-cell by the parasite, c, L. muris (after 

 Balfour), showing vermiform parasite which has divided the nucleus, d, L. musculi (after Porter), 

 surrounded by a clear cytocyst, lying in a mononuclear leucocyte. E, Leiecocytozoon {Haniamvebd) 

 ziemanni (after Laveran). The host cell is drawn out at either end, the nucleus of the host-cell is. 

 flattened, while the parasite appears as a vermiform cell in the middle of its host. 



may be somewhat narrower than those within the cells, and 

 have been well described as vermicules. This is especially the 

 case in L. funambuli (fig. 3, a). The leucocyte may endeavour to 

 protect itself from the action of the parasite by forming a capsule 

 or protecting layer around the invader, such a capsule being 

 termed a cytocyst (figs 1, d; 3, c). If a cytocyst be present 

 it is highly refractile and stains with difficulty. The internal 



