2U 



Mr. Arthur E. Shipley 



[Feb. 



coats, are extremely resistant and can endure for very long periods 

 without the death of their contents, which gradually divide to form 

 four smaller spores inside. The spores are scattered over the moors 

 by the action of the wind and rain, and, ahghting on the heather 

 or in the tarns of the moors, are taken up by the grouse in their food 

 or drink. When the cysts are swallowed they enter the gizzard of 

 the bird and pass unchanged into the first part of the intestine, called 

 the duodenum. Here the pancreatic juice is poured into the intestine 

 to aid in digestion, and under its influence the cyst-wall is softened 



Fig 



-Oocysts (cysts) of Eimeria (Coccidium) avium. 



A, oocyst (cyst) with contents completely filling it ; B, oocyst with con- 

 tents concentrated to form a central mass ; C, commencement of division of 

 the oocyst contents ; D, oocyst containing four rounded masses that will 

 become spores ; E, oocyst containing four sporocysts (spores) ; F, oocyst 

 containing four sporocysts, in each of which two sporozoites have formed. 



and dissolved, and the four small spores (contained within the 

 ripened spore or oocyst) are set at liberty. Each small spore contains 

 two active motile germs or sporozoites, which emerge from the softened 

 spore-case and proceed to penetrate the epitheUum of the duodenum. 

 The young parasites ultimately cause the destruction of the lining of 

 the first part of the small intestine — the region where, normally, 

 the most active digestive processes occur. The Coccidium parasites 

 multiply in the duodenal epithelium and then invade the ca^ca, or 

 " blind guts," with disastrous results. 



Sooner or later a limit is reached, on the one hand, to the power 



