Diseases of the Alimentary Tract 75 



Cole and Hadley ^ have advanced the claim that Black- 

 head (Enterohepatitis) is caused by a species of coccidium. 

 This view is not admitted by others. (For discussion see 

 pp. 94-99). Coccidia are, however, responsible for several 

 serious diseases of poultry. 



The question of the identity of species of coccidia attack- 

 ing fowl's, wild birds, and other animals has received con- 

 siderable attention. Fantham ^ has shown that the coccid- 

 ium of the grouse which causes the dwindling of the broods 

 in the early summer is equally injurious to young fowls and 

 pigeons. Some authors have claimed that the coccidium 

 of the rabbit (Eimeria (Coccidium) cuniculi) is identical 

 with that in birds. Fantham gives the results of experi- 

 ments which show that the organism from rabbits is entirely 

 distinct from that found in birds {Eimeria avium) and that 

 the former will not cause disease in birds. A similar con- 

 clusion is reached by Jewett ' except that he believes that 

 under certain conditions the coccidium from rabbits can 

 also produce disease in young chicks. 



Diagnosis. — There are no special external symptoms of 

 this disease until in an advanced stage. Adult fowls have 

 considerable powers of resistance to this parasite, and the 

 disease with them is more frequently seen in diarrhea, 

 a chronic form.' The symptoms are dullness, weakness, 

 sleepiness, diarrhea, and loss of weight, although the birds 

 retain their appetites for a considerable time. In many 

 cases the only symptoms are diarrhea, with loss of weight, 



1 Cole, L. J., and Hadley, P. B., "Blackhead in Turkeys." Rhode 

 Island Expt. Stat. Bui. No. 141, pp. 138-272, 1910. 



2 Fantham, H. B., "Cocoidiosis in British Game Birds and 

 Poultry." Jour. Economic Biology, Vol. 6, pp. 75-96, 1911. 



"Experimental Studies of Avian Cocoidiosis." Proc. Zool. 



Soc, London, Vol. 3, pp. 708-722, 1910. 



'Jewett, "Cocoidiosis of the Fowl and Calf." Jour. Comp. 

 Path, and Therap., Vol. 24, pp. 207-225, 1911. 



