1889.] PUBLIC DOCUMENT — No. 34. 129 



total number of cases reported. If these inferences be just, 

 the results which are furnished by my examinations certainly 

 do not exceed the actual number of infections which have 

 taken place as the direct result of eating trichinous meat. 



The important question, then, is: What are the sources 

 from which hogs get the infected meat? Fortunately, there 

 are not many ways in which it is probable that dangerously 

 infected meat could be got ; i, e. , there are not many animals 

 in which trichinae are found with sufficient constancy to 

 warrant one in supposing that they could furnish a con- 

 tinuous supply for infection. One of these animals is, of 

 course, the hog itself. But there is also another, — the 

 rat, — which, from its carnivorous, or at least omnivorous, 

 habits, is believed by many to be responsible for the per- 

 petuation of trichinae in hogs. Leuckart, who was the first 

 to call attention to the rat as a harbinger and probable dis- 

 seminator of trichinae, has given many reasons, both general 

 and special, upon which he bases his conclusions. 



But, while rats may be the principal cause for the per- 

 petuation of trichinae in Europe, it should not be overlooked 

 that nowhere else in the world has so great a proportion of 

 trichinous hogs been found as among this three thousand 

 raised in the vicinity of Boston. I cannot believe that the 

 conditions here are any more favorable for the perpetuation 

 of trichinae through rats than in European cities. I think 

 the hogs raised near Boston are not more closely confined, 

 and that they do not have more inducement or opportunity 

 to kill and eat rats, than in Germany. It must not be for- 

 gotten that the most of the hogs here reported on were not 

 raised in close quarters within the city limits, but by farmers 

 and hog-raisers in the suburbs, at distances varying from 

 five to twenty miles from the city proper. But, on the other 

 hand, it is undoubtedly true, that, wherever hogs are raised, 

 rats are more or less abundant. They are attracted by the 

 feed which is given to the hogs, and are likely to thrive 

 most where they have freest access to it. City otlal for the 

 hogs probably afibrds rats a better means of subsistence than 

 any kind of food which is better housed and cared for than 

 oflal is likely to be. So it may be that the offal is indirectly 

 responsible for the trouble, in that it serves to attmct more 



