INTESTINAL PARASITES. 3 15 



retain their vitality for a long time. But after being 

 expelled it is necessary for these eggs to mature, and con- 

 ditions favorable for their doing so are found in faecal mat- 

 ter, water or damp places ; and this essential stage of 

 development having been completed all is in readiness for 

 the final stage. Now let the eggs be taken up and enter 

 the stomach, and the young worms will burst the shells 

 and speedily mature. 



Such, in brief, is the course of infection with this worm; 

 and considering the ease with which it occurs it is not at 

 all surprising that puppies rarely escape it. 



A mother harboring the pests is constantly throwing 

 out of her body immense numbers of eggs, and these are 

 deposited about in her kennel and yard, in which, even if 

 the faecal matter is removed daily, some are sure to be left 

 and find here and there, upon the floor, sleeping-bench 

 and ground, the moisture which is necessary for their 

 development. Ignoring the danger of self-reinfection, and 

 assuming that she herself has been treated for worms and 

 all have been expelled, she must inevitably take immense 

 numbers of these eggs up in her coat and carry them with 

 her wherever she goes. Consequently, if removed from 

 her usual quarters to whelp, her new quarters must soon 

 become infested, the eggs being deposited over the floor, 

 on her bedding, etc. 



Clearly there is now absolutely nothing to prevent her 

 puppies from ingesting these eggs, even during the first 

 days of life, and swallowing them directly from her breasts, 

 hair, bedding or the floor ; and even did infection not 

 occur in this way it must subsequently occur through the 

 food or drinking water, from which it would be simply 

 impossible to keep the eggs, scattered about in such abun- 

 dance. 



Considering the size which worms in puppies have usu- 



