CHAPTER XXI 



SEROLOGICAL STUDIES WITH ENDAMCEBA 

 HISTOLYTICA 



By 



Charles E. Craig 

 Medical Corps, United States Army 



The biological activities of Endamwba Jiistolytica, the cause of 

 amoebic dysentery, have always excited the interest of the medical 

 zoologist, ov^ing to the great importance of this parasite as a patho- 

 genic organism living in man, and to the marked and charac- 

 teristic lesions which it produces frequently in the tissues of its 

 human host. For many years it has been known that this parasite 

 possesses the property of phagocyting the red blood corpuscles 

 of man and certain of the lower animals and of penetrating the 

 tissues of the intestine, producing necrosis and the formation 

 of ulcers and abscesses. It has also been found in other parts of 

 the body, as the liver, the brain, the testicles, and the skin, where 

 it produces abscesses of peculiar character ; while in experimental 

 animals, as the dog and cat, similar pathological lesions have been 

 produced experimentally by numerous observers. 



The theories regarding the biological activities of E. histolytica 

 until quite recently were based entirely upon clinical and patho- 

 logical observations, and this has been especially true of the ser- 

 ology of man and other animals infected with this parasite. This 

 has been due to the fact that it was not until recently that cultures 

 of this organism were available for use in experimental research, 

 but the successful cultivation of E. histolytica by Boeck and 

 Drbohlav (1925) and others has made possible more accurate 

 observations regarding this subject. 



In 1927, the author published observations demonstrating the 

 presence in alcoholic extracts of cultures of E. histolytica of 

 hemolytic and cytolytic substances. While the conception that a 



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