136 SOME MINUTE ANIMAL PARASITES 



young birds frequently do not have liver infection. 

 Sometimes the infected turkeys have been removed 

 to clean ground and the soiled area used for rearing 

 fowls, with fatal results to the latter. Similarly, 

 turkeys put on ground where outbreaks of coccidiosis 

 had occurred among fowls previously occupying it, 

 have succumbed to blackhead. Mutual infection 

 thus occurs, and soil fouled by turkeys or other 

 fowls should not be used for the rearing of young 

 bird stock of any kind. 



In the open country certain coprophagous (dung- 

 eating) flies, such as Scatophaga stercoraria, lay their 

 eggs in the droppings of birds, and there the larvae 

 develop. Larvae and adults taken from grouse- 

 droppings have been submitted to examination, all 

 possible care being taken to avoid external con- 

 tamination of the insects, and unchanged oocysts 

 have been found not only in their alimentary tracts, 

 but in their fasces voided during the time they were 

 kept under observation. A vigorous insect popula- 

 tion, then, can aid mechanically in scattering the 

 cysts of the parasite. 



" Prevention is better than cure " in all cases, 

 and nowhere does this apply more than in preserving 

 the health of domestic poultry and hand-reared game 

 birds, such as pheasants and partridges. Even in 

 epizootics among game birds it cannot be too 

 strongly insisted upon that all corpses of birds should 

 be burned and not buried. Every buried bird is a 

 new source of infection, and the polluted soil is 

 distributed in many and unseen ways by earthworms, 

 by round-worms of the soil, by carnivorous beetles, 



