TRICHINELLA SPIRALIS 



365 



develop in the uterus of the female and the minute young to 

 the number of at least a thous- 

 and are born alive. Soon after 

 birth, the young worms migrate 

 through the walls of the intes- 

 tine and, following the course 

 of the connective tissues, reach 

 the voluntary muscles of the 

 host, such as those of the limbs, 

 back, tongue, muscles of the 

 diaphragm and others. Each 

 worm then penetrates the sar- 

 colemma of the muscle fiber and 

 coils itself up in the muscle sub- 

 stance. A spindle shaped cyst is 

 formed around it, and the muscle 

 undergoes more or less degenera- 

 tion. This process gives rise to 

 various morbid symptoms in the p^^^ -,, Encapsulated Tri- 



host but, after some months the chinella spiralis in striated mus- 

 cysts become calcified and the ^le. X 60. (After Leuckart. ) 

 daneer to the infested individual is over. The flesh of a 

 "trichinized" human subject has been estimated to contain 

 100,000,000 and that of an infested pig 85,000 encysted 

 worms to the ounce. In order that further development of 

 the encysted and sexless trichinae should take place, it is 

 necessary for the infested flesh of the host to be eaten by 

 another animal in which the worm is capable of living, c. g., 

 that of man by a pig or rat, or that of a pig by man. When 

 this is done the cysts are dissolved by the digestive juices, the 

 worms escape, develop reproductive organs and copulate, the 

 young migrating into the muscles and producing the disease 

 as before. The result of eating an ounce of "trichinized" 

 pork, improperly cooked, might be the liberation in the intes- 

 tine of perhaps 80,000 worms, and if half of these were females, 

 each producing 1,000 embryos, some 40,000,000 worms would 

 shortly begin to migrate into the muscles and produce the 

 various symptoms of "trichinosis." 



