During the last twenty-five years, sizable segments of practically every population group in this country and abroad have been examined for intestinal parasites. As Faust and his colleagues1 have pointed out, "it is practically impossible to compare data on the parasite rates based on different population groups, utilizing different technics of diagnosis, and evaluating results according to individual idiosyncrasies." Nevertheless, because of such surveys it is now known that Endamoeba histolytica can be demonstrated wherever man is found without regard for race, latitude or social position. Furthermore, though accurate comparisons are impossible, it has been established beyond question that variation in incidence occurs among geographic, age and economic groups.
Craig,2 on the basis of such surveys, has estimated that between 5 and 10 per cent of the population of this country as a whole harbors Endamoeba histolytica. If it is important for medical men to appreciate the seriousness