Biology and Medicine 463 



and spread of the disease. There is no remedy known, save 

 that of prevention, and it is here, in the safeguarding of our 

 meat supply that the protecting hand of Uncle Sam is 

 stretched forth to save both the lives. and the dollars of his 

 children. 



Other parasitic worms of occasional occurrence in the 

 United States but of minor importance from a medical stand- 

 point, because of their relative benignity, are the tapeworms 

 transmitted to men in the flesh of both hogs and cattle. 



The story of the tapeworm briefly told is as follows: This 

 is as its name implies, a tape or band-like animal, divided 

 into segments which become progressively larger and riper in 



A TAPE WORM OF MAN 

 Courtesy of the U. 8. Bureau of Animal Industry. 



passing from the " anterior" or "head" end posteriori^. The 

 beef tapeworm lives in the intestine of man, and its ripe 

 proglottids are passed in the stools of the patient. These cast 

 proglottids are virtually nothing but a sack full of embryos, 

 each surrounded by a horny shell. If one of these embryos 

 is taken by the beef in its food or water, it loses its shell in 

 the beef's stomach and passes into the intestine as a tiny em- 

 bryo about 1/80 of an inch in diameter. This is armed with 

 three paired hooks by means of which the larva rapidly works 

 its way through the intestinal wall and into the blood vessels, 

 through which it is carried to the muscles or "flesh" of the 

 animal where it grows to a considerable size, acquiring the 

 "head" or attachment organ of the adult worm. The larva 



