INTESTINAL WORMS. 
129 
“ The ova of the Nematoicls, 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, whore it. is 
afterwards to pass its life.” 
i 
