284 



DISEASES OE THE LIVER, 



Hosts. Dog, dingo, jackal, wolf. 



Life history. Starting with the adult tapeworm (Fig. 124) in the 

 small intestine of the dog or wolf, the eggs are scattered over the ground 

 and are swallowed by the intermediate host with the fodder or water. 

 Upon arriving in the stomach the egg-shell is destroyed, and the six- 



FiG. 123. — Portion of the intestine of a 

 dog infested with the adult hydatid 

 tapeworm ( Tcenia echinococctis, 

 natural size. (After Ostertag, 1895.) 



Fig. 125. — Hooks of adult hydatid tape- 

 worm, a, From a hydatid ; b, three 

 weeks after feeding to a dog ; c, from 

 an adult ; d, combined figures of a — c, 

 showing the gradual changes in form. 

 X 600. (After Leuckart, 1880.) 



Fig. .124.— Adult hydatid tapeworm 

 {Tcenia ecJiinococcus) enlarged. 

 (After Leuckart, 1880.) 



hooked embryo, which is thus freed, bores its way through the intestinal 

 wall, and wanders, actively or passively (that is, carried along by the 

 blood), to various organs of the body — liver, lungs, ovaries, bones, skull, 

 etc. — where it develops first into an aceplialoci/st, which may develop 

 further, as shown by the accompanying illustrations. The heads which 

 are formed, upon being devoured by a dog or wolf, then develop into 

 adult tapeworms. 



