OUR UNBIDDEN GUESTS. 83 



already remarked, in an imperfect and youthful con- 

 dition. If the pig lives long enough, the trichinae 

 will disappear from its muscles, or will degenerate to 

 become mere specks of lime. But should a man eat a 

 portion of the trichina-infected pork, the youthful 

 worms will undergo, in his digestive system, a rapid 

 and extraordinary development. The trichinae will 

 develop enormous numbers of young; and the young 

 brood will now naturally seek the muscles of man for 

 a habitation, as their parents before them sought 

 those of the pig. Then ensues the tug of war for the 

 afflicted human. The pain caused by the boring of 

 these microscopic worms from stomach to muscles is 

 intense. It is this pain and attendant symptoms 

 that constitute the disease known as trichiniasis. If 

 the patient's strength holds out, he is safe whenever 

 the young trichina-brood enter the muscles. There 

 they rest, and remain to degenerate -^unless, indeed, 

 cannibal instincts were represented in the human race; 

 in which case the cannibal would experience a few of 

 the tortures and troubles which are said proverbially 

 to afflict the just and unjust alike. 



The great lesson to be learned, from our survey of 

 parasites, is care in the choice and increased care in 

 the cooking of our food. It should be remembered 

 that the germs of these parasites are killed by a suffi- 

 ciently long exposure to heat. Hence, while under- 

 done meat may have its charms, it has likewise its 

 grave dangers. Pork, in any and every fashion, should 

 at all times be thoroughly cooked. In this latter case, 



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