INTESTINAL WORMS, 



129 



" The ova of the Nematoids, after passing into the bodies 

 of animals with their food, insinuate themselves into the 

 walls of the intestine, so that their presence completely 

 escapes detection. In this position these ova undergo a 

 sort of incubation, and the embryo becomes sufficiently 

 developed to return into the intestinal cavity, where it is 

 afterwards to pass its life." 



