102 



the habits of the swine. Accordingly, neither man nor the hog 

 presents the proper theoretical conditions for the perpetuation of the 

 parasites and hence to serve as reservoir for the disease it causes. 



Rats, on the contrary, are cannibalistic, and trichinosis is a com- 

 mon disease among them. Hence they may be viewed as the natural 

 reservoir for the parasites and for the disease it causes; hence, also, 

 any well-directed public health campaign against trichinosis should 

 consider the eradication of rats. 



Rats become infected by eating each other; by eating scraps of pork 

 found on the offal pile of slaughterhouses, or in swill ; and by eating 

 scraps of human flesh in dissecting rooms of medical schools. 



FIG. 31. Female trichina from the intestine; 24 hours after infection. 



1866a, pi. 1, fig. 1.) 



Enlarged. (After Leuckart, 



Swine become infected by eating rats, and by eating scraps of pork 

 on the offal pile of slaughterhouses, or in swill. 



Man becomes infected almost exclusivly by eating pork and boar 

 meat. The rare infections which occur from eating other meat are 

 almost negligible. 



MEDICAL SIGNIFICANCE. Trichiniasis or trichinosis refers to infec- 

 tion with the trichina or flesh worm. Normally it occurs only in 

 mammals, chiefly carnivorous and omnivorous species, and it is 

 transmissible from any infected mammal to any other mammal sus- 

 ceptible to it, in case the latter eats the uncooked flesh of the former. 



