TRICHINIASIS OF MAN AND ANIMALS. 31 



Of 320 rats from other places, 39 were found trichinous — 11 per 

 cent. 



Of 51 rats caught at a knacker establishment at Spectacle Island, 

 Boston Harbor, I found 39 trichinous. 



The proprietors of this place kindly gave me opportunity to 

 examine twenty-eight hogs, which had been kept and fattened by 

 them at the island in question. None were found trichi?ious. These 

 hogs received no city swill of any kind. What flesh they received 

 had been subjected to the heat necessary to extract the fats ; other- 

 wise^ they received nothing but corn-meal. 



Forty rats caught at one of the large packing-houses near Boston 

 were all found trichinous. 



Of sixty rats caught for me at different stables in the city of Bos- 

 ton, where no hogs were or had been kept, but six contained trichinw. 



I can not see any just grounds for accepting the rat-infection 

 theory ; i. e., that swine become invaded in the majority of cases 

 from eating trichin-invaded rats. In fact, I am strongly inclined 

 to think that quite the contrary is the case ; though I willingly 

 admit that an occasional hog may become invaded in this manner. 

 My own observations would seem to prove that whenever rats have 

 opportunity to get at the trimmings or refuse of slaughtered hogs, 

 there the rats will be found to be most profusely trichinous ; while 

 in other localities it will not be so. 



Admitting that an occasional rat may lead to trichin invasion 

 among hogs, we have still the open question, Is there no common 

 source from which not only swine and rats, but wild animals, may 

 derive this parasite f As, according to my own observation upon 

 American pork, and my very limited examinations of American 

 rats, they are both more largely invaded by trichinae than similar 

 animals in Germany, it seems as if here in America were the place 

 to study and decide these important questions. 



It will not do for us to falsify or ignore true facts. The man- 

 ner hitherto adopted of asserting, by way of pure negation, that 

 "American pork has no trichinae," as the pork interest has done, 

 will not do. We must stand on facts gained by accurate and trust- 

 worthy observers. We must accept them. We must search for 

 the cause. Any other course is absurd, and equally ruinous to self- 

 respect. 



Prevention of Tkichen^e in Swine. 



1. Boards of health should take means, looking to the better 

 education of the people in relation to hog-raising, as well as all the 

 principles of animal hygiene. 



