THE PROTOZOAN SUBGROUPS 345 



Plate VIII. — Coccidian Life Cycle. — Fig. 1. 1. Sporozoite released in intestine of 

 host. 2. Penetration of sporozoite into epithelial cell. 3, 4. Growth of sporozoite into 

 trophozoite. 5, 6, 7. Schizogonous cycle. Nuclear division, followed by division of 

 entire trophozoite into a large number of merozoites. 8. Free merozoites, which for an 

 indeterminate number of generations merely repeat the schizogonous cycle, behaving 

 precisely as do the sporozoites. Eventually, however, the sporogonous cycle is initiated, 

 which proceeds as follows: 9a. Undifferentiated female cell. 9b. Undifferentiated male 

 cell. 10a. Differentiated female cell. 10b. Differentiated male cell. 11, 12. Formation 

 of the microgametes, one male cell producing many microgametes. 13a. Macrogamete. 

 One female cell produces but one macrogamete. 13b. Ripe microgamete. 14. Fertiliza- 

 tion. 15, 16, 17. The zygote. 18. Beginning of spore formation. 19. Completion of 

 spore formation. 20. Formation of the sporozoites within the spores. 21. Release of the 

 sporozoites in the intestine of the host. Fig. 2. — Introduced for comparison with the 

 more typical cycle shown in Fig. 1. Here the parasite penetrates and comes to rest in the 

 nucleus instead of the cytoplasm, and there is sexual differentiation in the schizogonous 

 cycle as well as in sporogony. (After Crawley, from Mense's "Handbuch," after 

 Schaudinn, Cir. No. 194, Bu. An. Ind., U. S. Dept. Agr.). 



suggested: Pearson's creolin well diluted with milk or water, also large 

 doses of camphorated tincture of opium, and rectal injections, using 

 garden hose and funnel, of a two per cent, creolin solution, alternating 

 night and morning with a one per cent, alum solution. A week later 

 received word that all were doing nicely and no deaths." 



In Europe outbreaks of red dysentery similar to that of cattle have 

 occurred in sheep. 



CocciDiAL Enteritis of Chicks 



The use of the name "white diarrhea" for this coccidiosis tends to its 

 confusion with bacillary white diarrhea, which is a fatal septicemia of 

 chicks caused by Bacterium pullorum. Coccidial enteritis or coccidiosis 

 of chicks is caused hy Eimeria avium {Coccidium tenellum), which attacks 

 the epithelium of the intestinal mucosa, usually that of the ceca. Occa- 

 tionally the infection is found in other organs. The disease is usually 

 seen in chicks from two to ten weeks old. 



Symptoms. — The symptoms are merely suggestive of coccidiosis as 

 they do not materially dijffer from those of some other diseases of poul- 

 try. The affected chicks droop and are inclined to stand about by them- 

 selves with eyes closed and feathers ruffled. In most all cases there is a 

 diarrhea with whitish-colored discharge which stains and mats the 

 feathers below the vent; a bloody diarrhea gives evidence of coccidial 

 infection. If the discharge is examined under the microscope large 

 numbers of circular or slightly oval o6 cysts may be found . Death usually 

 occurs after a course of three to four days. 



Post-morten Appearance. — Post-mortem examination reveals the 

 ceca much enlarged. Their contents may be normal or they may be 

 packed with a yellowish white or bloody semiliquid material. The 

 conclusion that the chicks are not infected with coccidia should not be 

 made from the absence of enlarged ceca, as occasionally there is no 



