DISEASES OF THE HOG. gj 



Figure 76. — This very minute worm is found in 

 the larva stage in large numbers in the flesh of 

 some pigs, dogs, cats, rats, mice, rabbits, guinea- 

 pigs and many other animals, in the natural state 

 in the intestines of the same animals. The male is 

 very small, measuring only one-eighteenth of an 

 inch. The female is stouter and longer than the 

 male, measuring about one eighth of an inch. The 

 young trichinae occur embedded in the muscles of 

 the pig and various other animals. They are so 

 small as to be quite invisible to the eye and mill- 

 ions of them may be in the flesh of the pig without 

 producing any unusual appearance; even an ex- 

 pert could not detect them without the aid of the 

 microscope. This is why so many deaths occur 

 from eating pork filled with this parasite. When 

 these little worms are first introduced into the mus- 

 cles of the pig they are free and coiled up among 

 the fibers of the muscles; but after a few weeks they 

 become incased in minute whitish, elongated cysts, 

 supposed to be the result of irritation set up by 

 their movement and feeding. Figure 76. In a year's 

 time these cysts become calcified by a deposit of 

 carbonate of lime in the membrane; when this 

 takes place minute white specks about the size of 

 hemp-seeds may be seen in the muscles. When 

 the worms are inclosed in the cyst they lie dormant 

 and although they may live for years and even 

 weeks after the death of their host they can do no 

 further harm, unless they are eaten by man or some 

 animal. Each cyst contains a little slender worm 

 about one twenty-fifth of an inch long and one sev- 



