694 INFECTION AND IMMUNITY. 



diarrheas (typhoid, cholera, mucous colitis, etc.,) 

 and inhabits especially the upper and middle por- 

 tions of the intestines. It is evacuated in consid- 

 eral numbers following administration of cathar- 

 tics. It appears not to be of much pathogenic sig- 

 nificance, but finds in the liquid stools and in an 

 alkaline reaction conditions which favor its prolif- 

 eration. It may be transmitted as a contagion 

 (Epstein). 



Other species of trichomonas occur in the intes- 

 tines of different animals. 



other Other less important flagellates are: Lamblia 

 Flagellates. i n ^ es ^ na n Sf found in the intestines of many ani- 

 mals and in man in Germany, Italy, Kussia and 

 Sweden; Bodo urinarius (Cystomonas urinarius, 

 Plagiomonas urinaria), found in the urine in cys- 

 titis (Kiinstler). 



IX. COCCIDIOSIS. 



Coccidia are essentially cell parasites, preferring 

 the epithelial cells of the intestines and liver, al- 

 though they may be carried to other organs. They 

 have an alternating asexual and sexual cycle of 

 development. The young sickle-shaped and nu- 

 cycles, cleated sporozoite penetrates an epithelial cell, 

 grows in size, and the nucleus subdivides many 

 times to form new young cells, which eventually 

 escape again as sickle-shaped sporozoites. This 

 asexual process is called schizogony. Several stages 

 of schizogony may follow successively, but event- 

 ually the organisms lose their proliferative power 

 unless they are fortified by a sexual cycle. In the 

 sexual cycle (sporogony) some of the sporozoites 

 become differentiated into larger granular cells 

 (female) and others into smaller cells (male). 



