132 SOME MINUTE ANIMAL PARASITES 



down the gut and reach these caeca. Cases are 

 known in which birds have recovered from coccidial 

 infection of the duodenum, but have succumbed to 

 that produced later in the caeca. Duodenal infection 

 is quite enough to kill young birds, even when not 

 supplemented by caecal infection. The larger the 

 number of oocysts swallowed originally, the greater 

 is the chance of the parasite propagating enormously. 

 In such cases, or where a succession of crops of 

 oocysts are swallowed by the bird, the intestinal 

 epithelium gets little or no chance to regenerate. 

 Digestive troubles ensue, anaemia and wasting follow, 

 and death ultimately cuts short the career of the 

 host, and also to some extent that of the parasite, 

 since young, developing forms of Eimeria perish 

 with their host and rapidly degenerate. 



Such is very far from being the case with the 

 oocysts that have already been fertilized. So far 

 from perishing on the death of their host, they 

 remain within the body, and their further develop- 

 ment is aided by the heat produced by the decay of 

 their victim. ' When at last they are set free by the 

 rapid disintegration of the tiny corpses of birds, such 

 as young grouse or pheasants, they contaminate the 

 soil, and another bird, perchance in search of grit or 

 insects, takes up the polluted soil, and thereby sows 

 within itself the germs of its own destruction. 

 While it is almost impossible to prevent such con- 

 tamination among wild birds, it is less difficult in 

 the case of domesticated ones. But in all cases it 

 cannot be too strongly emphasized that any corpses 

 found should be burned and not buried. It is not 



