"GROUSE DISEASE " COCCIDIOSIS 255 



appearance, owing to the bluish coloration. Leg weakness is 

 often present. 



The plumage of the infected birds is affected in regions 

 other than the head, and the quills are less rigid than in normal 

 birds. The feathering of the legs is ragged, and the sheen on the 

 neck and tail-coverts is not so well developed, while the replace- 

 ment of nestling-down by ordinary feathers is much retarded. 



During the progress of Coccidiosis the birds sometimes 

 develop much mucus, and a very offensive " breath," a smell of 

 sulphuretted hydrogen being noticeable. Both sticky mucus 

 and smell disappear as a rule in a few days, but may recur. 



A day or so before the death of the infected bird the slimy, 

 mucilaginous discharge recommences, oozing from the beak, 

 nares, ears, and eyes. Examination of this liquid by the 

 microscope shows the presence of oval coccidian oocysts. The 

 ooze from the eyes and beak chiefly contains oocysts which may 

 be due to regurgitation from the crop just before death. How- 

 ever, it should be noted that while mucous discharge is common, 

 it is not an invariable feature of Coccidiosis. Oocysts are 

 occasionally present in the crop and gizzard, mixed with crushed 

 food, having probably been taken up with the food. 



Death from Coccidiosis appears to be sudden. Some of 

 the experimental fowl chicks were feeding greedily an hour 

 before death, though death was almost expected from the great 

 emaciation and " bluish " appearance of the birds for some days 

 previous to the actual decease. 



Detailed examination of the internal organs of diseased birds Effects on 

 shows that Coccidiosis is confined chiefly to the main digestive 

 tract, and so is unlike the Coccidiosis of the rabbit where the 

 liver as well as the gut may be affected. 



Death of the young Grouse may occur owing to heavy 

 infection in the duodenum, whereby almost the entire lining 

 of this part of the gut may be destroyed by the action of the 

 parasite. In many cases, however, some of the merozoites pass 

 along the intestine and reach the caeca, the tissues of which are 

 similarly invaded and mutilated. The exact shape and size of 



