55 



history of one of the comimou tapeworms of man 

 {Tcenia soleum) usually called the "pork tapeworm." 

 The eggs from the mature tapeworm oi this species 

 pass from the body of a person harboring it and some 

 of them are consumed by swine. They hatch out in 

 the stomach or intestines of the swine, penetrate tlie 

 intestinal walls and reach the muscular portion of the 

 animal. There, they constitue the so-called "bladder 

 worm" or "measles" of pork. 

 The hog is slaughtered and if 

 its flesh is eaten raw or imper- 

 fectly cooked, the consumer £• 

 swallows the living parasites g 

 which develop in the intestinal 5 

 canal into mature tapeworms, o 

 In the same way it is neces- > 

 sary for the tapeworms of fowls o 

 to pass through the body of an ^ 

 intermediate host before they g 

 can re-appear as tapeworms in | 

 fowls. It has been shown by 5* 

 definite experiments and numer- 5 

 ous observations that the inter- o 

 mediate hosts in some cases are *^ 

 small animals such as snails, ^ 

 molluscs, worms and insects § 

 and it seems probable that these ^ 

 animals are the intermediate % 



hosts for bird tapeworms in all ^ 



o 

 cases. » 



s 



A single ta]>eworm in the in- " 

 testinal canal of a fowl may do 

 no harm. But when they are 

 numerous symptoms of disease appear. One of tlu' 



