ENDAMCHBA GINGIVALIS 



Howitt ( 1926b) finds that washed red cells of the guinea- 

 pig are eaten by specimens in artificial cultures, but 

 erythrocytes are probably very seldom devoured in 

 nature. The colonization of the intestine by this species 

 as a result of swallowing trophozoites seems impossible 

 according to the work of Howitt (1926b), who found 

 that they were unable to withstand human gastric juice 

 containing the normal amount of acid, and quickly ex- 

 ploded when subjected to human bile. 



Host-parasite specificity. Amoebae have been found in 

 the mouths of certain lower animals. Goodrich and 

 Moseley (191 6) reported them from the dog and cat 

 suffering from pyorrhea, and Nieschulz (1924) de- 

 scribed what he considers a variety of the human species 

 E. gingivalis var. equi from around the teeth of the horse. 

 It remains to be determined whether these are specifically 

 distinct from the species occurring in man. Hecker 

 (1916) found it impossible to infect guinea-pigs with 

 amoebse from the human mouth and Drbohlav (1925a) 

 was equally unsuccessful with a kitten into the intestine 

 of which he injected specimens grown in culture and in a 

 young dog into the gingivae of which similar material 

 was inoculated. 



127 



