HOST-PARASITE RELATIONS: INTESTINAL PROTOZOA 



cent and 1.7 per cent respectively with E. coli. Interesting 

 comparisons between Chinese and foreigners as regards 

 susceptibiHty to infection with E. histolytica and with 

 respect to the severity of the infections have been pro- 

 vided by Kessel and Svensson (1924) and Kessel and 

 Willner (1925). A survey in Peking by the former 

 showed that infection in Chinese (29.5 per cent) was 

 considerably greater with this species than in foreign- 

 ers (16.5 per cent). Kessel and Willner (1925) report 

 a careful study of 1800 patients admitted to the Peking 

 Union Medical College Hospital between October i, 1923, 

 and May 31, 1924. Of these 129 were positive for E. 

 histolytica on stool examination. Five groups were rec- 

 ognized by these investigators, according to the charac- 

 ter of the symptoms as follows. 



These results show that foreigners exhibit both more 

 severe and more mild symptoms than Chinese and are 

 correspondingly low in the number of healthy carriers 

 when compared with the Chinese. These data indicate 

 that although the Chinese are more highly infected their 



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