﻿IX, B, 1 Willets: Intestinal Parasitism 91 



when acute dysentery develops ? Is it crowded out by the rapid 

 multiplication of E. histolytica? Are there so many active E. 

 histolytica present in dysenteric stools that the relatively few 

 active E. coli are overlooked even in a careful search? Does 

 the sluggishly moving, porcelaneous E. coli take on activity and 

 a hyaline appearance in dysenteric stools so that it simulates 

 E. histolytica, just as the latter changes in motility and general 

 appearance so that it resembles the former in nondysenteric, 

 unformed stools ? If the evidence obtained in numerous investi- 

 gations were less strong, would not the very frequent association 

 of E. coli and E. histolytica cysts in nondysenteric individuals, 

 the impossibility of accurately differentiating the quiescent and 

 active entamoebae found in nondysenteric stools including those 

 obtained after the administration of a saline cathartic, and the 

 almost exclusive occurrences of pure E. histolytica infections in 

 the stools of persons suffering from entamoebic dysentery tempt 

 one to believe that, after all, there is but one species of Entamoeba 

 in man and that its appearance varies under different circum- 

 stances? These are grave questions which demand answers. 



SUMMARY 



1. Entamoebic infections were found in 37.5 per cent of the 

 1,000 individuals examined, in 38.8 per cent of 900 Filipinos, in 

 26.0 per cent of 100 Americans, in 46.3 per cent of 417 adult 

 female Filipinos, in 34.2 per cent of 383 adult male Filipinos, 

 in 25.0 per cent of 100 Filipino children, in 25.4 per cent of 71 

 adult male Americans, and in 27.6 per cent of 29 adult female 

 Americans. Double infections were found in 59.2 per cent, pure 

 E. coli infections in 35,5 per cent, pure E. histolytica infections 

 in 5.3 per cent, E. coli infections in 94.7 per cent, and E. histoly- 

 tica infections in 64.5 per cent. If more stools had been ex- 

 amined of each patient, it is believed that the positive percentage 

 would have been about 55 instead of 37.5. 



2. Percentage of entamoebae infection reported for the Phil- 

 ippine Islands by various investigators have varied from to 76. 

 This is believed to be explained in a large degree by the varying 

 conditions under which the examinations have been made. 



3. Diagnosis of entamoebic infection should be made not only 

 upon the presence of active, but also upon that of quiescent or 

 encysted forms. 



4. The one safe stage of development for a differential diag- 

 nosis between E. coli and E. histolytica is the encysted form 

 encountered in formed stools. 



