428 



THE ANIMAL PARASITES OF MAN 



an important factor ; for instance, the custom of eating pork in 

 a condition that does not affect the life of the enclosed trichinella. 

 In places where such customs do not prevail, epidemics do not 

 occur at the most there are isolated cases of the disease, although 

 there be a great number of infected pigs. The following conditions 

 prevail in North America : In Boston, Billings found that 4 to 5*7 per 

 cent, of the pigs examined were trichinous ; Belfielcl and Atwood 

 found that 8 per cent, were infected in Chicago ; Salmon found 

 on an average that 27 per cent, were infected (but at various places 

 the percentage fluctuated between 0*28 to 16*3 per cent.), yet epidemics 

 of trichinosis hardly ever occur in North America, and only isolated 

 cases of the disease are met with in German immigrants, who keep 

 to their native customs. 



This report, according to the researches of H. U. Williams, must be consider- 

 ably modified. This author has examined the muscular system of human cadavers 

 according to the method employed by inspectors of meat for pigs. The investiga- 

 tions were conducted in the Pathological Institute of the University of Buffalo, and 

 the observer has examined 505 bodies since 1894, of which J7 (= 5-34 per cent.) 

 were invaded by Trichinella. The cases, according to the nationality, are divided 

 as follows : 



It is worthy of remark that half of all the positive cases were mental patients, 

 who were found to be affected with Trichinella to well-nigh 12 per cent. Trichinosis 

 was not, however/the cause of death in any case. Very frequently the Trichinella 

 were found calcified and dead. 



Conditions are similar in most countries of Europe, where, of 

 course, the number of infected pigs is considerably smaller, but 

 the disease depends less on this than on the way in which the 

 pork is prepared. 



Cases of trichinosis have been known to occur in nearly all 

 the countries of Europe; further, in Egypt, Algeria, East Africa, 

 Syria, India, Australia, and America. North Germany, more 



