96 



THE INTERNAL PARASITES OF 



The Gid Tapeworm. — The veterinarian and agriculturist 

 are alike interested in the facts connected with, the deve- 

 lopment of this parasite (Tcenia coenurus). In the full- 

 grown state this worm varies from twenty to fifty inches 

 in length. It cannot be said to be common in this 

 country,, and probably does not occur in more than five 

 per cent, of our dogs. In Iceland, however, as Dr. 

 Krabbe has shown, it occurs in 18 per cent, of the native 

 dogs. Its prevalence, no doubt, bears a strict corre- 

 spondency to the amount of u gid disease " existing in 

 any country. 



Fig. 19. Larv^: of the Gid Tapeworm. 



In order to understand how the dog obtains this tape- 

 worm, it must be observed that gid hydatids, or coenuri, 

 each represent a sort of colony of larval parasites. When, 

 therefore, the dog eats a sheep's brain containing a single 

 hydatid, he swallows a colony of larvae, each of the latter 

 being destined to become transformed into a tapeworm 

 in the bowel. Thus, Fig. 19 represents two hydatids, one 

 being viewed from without, and the other from within. 

 At A the young tapeworm heads are seen projecting 

 from the exterior surface of the hydatid ; whilst at B they 

 are seen retracted within the interior of the bladder 



