GROUSE DISEASE' 1 COCCIDIOSIS 



247 



wards in the laboratory and experimental station, form the 

 subject of the present chapter. The experimental results 

 throughout have been carefully compared with those of natural 

 Coccidiosis occurring in wild Grouse-chicks picked up on the 

 moors each subsequent season. 



The Coccidium found in the gut of the young Grouse is known 



TEXT Fia. 35. 



Stages in the development of the oocysts of Eimeria avium, as 

 seen in fresh preparations. 



A. Cyst (more correctly oocyst) with protoplasm completely filling it. 



B. Older oocyst with contents forming a central sphere. Many such 



cysts are found in infected caeca and infected freces of Grouse. 



C. Oocyst with four nuclei, about to form young spores. 



D. Oocyst with four round spore masses. 



E. Four ovoid spores (or sporocysts) within oocyst. 



F. Fully mature oocyst with four spores, each containing two sporozoites. 



The Coccidian oocysts are about one-hundredth the size of a small gi;ain of wheat. 



to science as Eimeria (Coccidium) avium, and is a protozoal 

 parasite invisible except under high powers of the microscope. 



Coccidiosis has long been known as a disease of rabbits, 

 and is often fatal, but the species of Coccidium which attacks 

 rabbits is different from that which affects Grouse, for Grouse 

 chicks into which the Coccidium of the rabbit has been artificially 



