COCCIDIUM 253 



Bass, of New Orleans, claims to have successfully cultivated 

 malarial plasmodia of the species vivax and falciparum by the use 

 of human blood. He has also succeeded when using Locke's fluid 

 minus calcium chloride plus ascitic fluid. One-half percent dex- 

 trose is usually added. The blood is drawn, so that it can be 

 defibrinated, into small flat-bottom tubes. These are incubated 

 at 4oC. The column of fluids is 1-2 inches high, the clear serum 

 layer being % inch at least. The parasites grow in the upper 

 layer of the cellular sediment. Undiluted serum and leucocytes 

 are lytic for plasmodia. For renewed cultures these must be 

 removed but uninjured red cells must be added. Only the asexual 

 division has been observed. Leucocytes phagocyte pll free 

 parasites under artificial conditions. 



COCCIDIUM 



Coccidium hominis is another member of the sporozoa that occa- 

 sionally infects man. Coccidia are infectious also for horses, 

 goats, oxen, sheep, pigs, guinea pigs, weasels and rabbits. The 

 organism is essentially a cell parasite inhabiting the cells of the 

 gastro-intestinal tract by preference, chiefly the liver and intes- 

 tinal mucous membranes. They lead a sexual and asexual 

 existence like the malarial parasites (alternate generation). The 

 young sickle-shaped nucleated sporozoite penetrates an epithelial 

 cell, where it gradually develops, ultimately dividing into numer- 

 ous sporozoites. This is the asexual stage of development 

 (schizogony) , the sexual stage being called sporogony. 



The sporozoites are differentiated into the two sex elements. 

 These are large granular appearing cells; the male being smaller, 

 divides into numerous flagellated microgamates that penetrate the 

 female granular cells, macrogametes, and fertilize them. These 

 fertilized macrogametes, or zygotes, form capsules and become 

 oocysts which divide into numerous sporoblasts, changing into 

 sickle-shaped sporozoites upon liberation. 



