TRICHINOSIS — SCHWARTZ 427 



fection on farms in the areas mentioned are the contents of the 

 scrap barrel, offal from hogs butchered on farms and in country 

 slaughterhouses, dead hogs, dogs, cats, and rats which are not prop- 

 erly disposed of and are available to pigs, and are probably eaten 

 by them, particularly when the latter are affected by some nutritional 

 deficiency. 



Since the incidence of trichinae in the 6,484 hogs fed on raw 

 garbage was 4.41 percent, nearly five times as great as that in the 

 series of grain-fed hogs, it is safe to conclude that the feeding 

 of uncooked garbage favors the spread of trichinae to swine. Al- 

 though the bulk of garbage that is fed to swine consists of vegetable 

 matter, raw pork bones with adhering meat, and trimmings con- 

 taining small portions of swine muscle tissue are also likely to be 

 present. As a small percentage of swine muscle tissue may contain 

 living trichinae, the continued feeding of uncooked garbage is apt 

 to result and does result in the continuation of the vicious cycle of 

 trichinae in a relatively large proportion of such hogs. 



As an alternative to the elimination of garbage feeding alto- 

 gether, cooking of garbage to a temperature sufficient to destroy 

 the vitality of all live trichinae that may be present in pork con- 

 tained in it is a procedure that should be given careful considera- 

 tion by garbage-feeding establishments and adopted as an alternative 

 to the feeding of garbage as collected. The data already presented 

 show that out of nearly 2,000 samples of diaphragm muscle tissue 

 obtained from hogs known to have been fed on cooked garbage, only 

 about 0.5 percent were found to be infested with trichinae, and of 

 those so infested nearly 50 percent contained negligibly small num- 

 bers of these parasites. Another possibility, more applicable to the 

 farm than to garbage-feeding establishments, is the elimination of 

 meat from feed intended for hogs. 



The control of trichinae in swine has been of interest to the United 

 States Government since 1881. As already stated, the earlier inves- 

 tigations on trichinae by scientists of the Bureau of Animal Industry 

 were stimulated largely by the restrictions placed by various foreign 

 governments on the importation of pork from this countr3\ Ac- 

 tually, however, nearly all the pork shipped from the United States 

 to Europe in the last few decades of the nineteenth century was 

 exported in the cured state, and it has been known for a long time 

 that thorough curing is destructive to trichinae. To meet the slurs 

 cast by certain European countries on the United States livestock 

 industry, Dr. Daniel E. Salmon, the first chief of the Bureau of 

 Animal Industry, detailed to Gennany Dr. Charles W. Stiles, at 

 that time zoologist of the Bureau, to investigate outbreaks of trichi- 

 nosis in that country, alleged to have resulted from the consumption 



