306 ^^^ Philippine Journal of Science wis 



bacteriologically sterile, Entamoeba histolytica is found not so 

 much in the necrotic material as in the sound tissues at the 

 borders of the abscess. 



Anatomically and histologically both the intestinal and liver 

 lesions are characteristic and do not correspond to lesions due 

 to other microorganism. The typical ulcerations are of the 

 so-called undetermined type, which undoubtedly result from 

 the widespread wandering of Entamoeba histolytica in, and the 

 consequent histolysis of, the tissues underlying the intestinal 

 epithelium. The cellular reaction about those lesions, when un- 

 complicated by secondary bacterial invasion, is not inflammatory 

 but regenerative in character and consists not of polymorphonu- 

 clear leucocytes but of formative cells and lymphocytes. In liver 

 abscesses, which are less frequently complicated by secondary 

 bacterial infection than are the intestinal lesions, the nature of 

 the morbid process is most clearly perceived. The so-called 

 pus of these abscesses is not pus at all, but chiefly cellular 

 detritus resulting from the histolysis of the liver tissue by Enta- 

 moeba histolytica. 



In the experimental infections with Entamoeba histolytica no 

 dysenteries have developed in the cases parasitized from a case 

 of acute entamcebic dysentery, in those from an entamoebic liver 

 abscess, nor in those who did not become parasitized with Enta- 

 moeba histolytica, although the acidity of the stomach contents 

 of all of these men was neutralized with magnesium oxide at the 

 time of ingestion of the infectious material. If a bacterium or 

 other unidentified microorganism should be concerned in the 

 etiology of this disease, it would seem that these feeding experi- 

 ments were made under conditions most favorable to secure 

 infection. 



On the other hand, all of the experimental dysenteries were 

 obtained after ingesting Entamoeba histolytica from healthy 

 persons who were "carriers" of this parasite. Case 2 developed 

 dysentery after ingesting Ejitamoeba histolytica from a man con- 

 valescent fifty-nine days from a slight spontaneous attack of 

 entamoebic dysentery, who has not subsequently shown any symp- 

 toms of dysentery, and who was, therefore, a "convalescent 

 carrier" of Entamoeba histolytica. Case 30 resulted from the 

 ingestion of material from the same carrier convalescent one 

 hundred sixty-one days. Case 39 suffered an attack of enta- 

 moebic dysentery after ingesting Entamoeba histolytica obtained 

 from a person who had not, and has not subsequently, developed 



