80 VETERINARY PARASITOLOGY 
spermosis) which they produce. Coccidium Zurni is 
responsible for outbreaks of dysentery in young cattle 
and lambs, while Coccidium oviforme produces similar 
symptoms in rabbits. Sir John MacFadyean found 
Coccidia in cattle indistinguishable from Coccidium 
oviforme. The Coccidia are ovoid in shape, and possess 
an outer envelope, which gives the parasite a double 
contour when examined microscopically. 
The contents of the capsule or envelope are granular, 
and may assume various forms and positions, according 
to the stage of development. 
The length is 18 to 25 yw, and width about 13 p. 
Desiccation destroys the Coccidia, and they are therefore 
prevalent on low-lying, marshy ground. 
Symptoms.—At first the animals void greenish-black, 
foetid, liquid feeces, and there is no straining and little 
constitutional disturbance. In a few days this gives 
way to dysentery, with a large proportion of blood 
mixed with the feces. The animals now appear dis- 
tressed, strain forcibly for some minutes after defecation, 
arch the back, and may show colic. There is loss of 
appetite and absence of thirst, and emaciation sets in 
very rapidly. The course of the disease lasts about a 
week. Mortality may be anywhere from Io to 25 per 
cent. 
Lesions.—These are present in the whole length of the 
large intestine. The bowel is empty, the mucous mem- 
brane inflamed and discoloured, thickened and ridged, 
and shows areas coated with a thick tenacious layer of 
mucus. On removing this, the mucous membrane 
beneath appears whitish and shows depressed ulcers. 
On microscopical examination of a section the 
parasites are seen to have invaded the crypts of 
Lieberktihn, and to be present both in the lumen of the 
ducts and in the cells themselves. The interglandular 
connective tissue is infiltrated and thickened. 
