A micromanipulator of original design was used for transfer of single amebae from the S-F medium in test tubes to microcultures. Quantitative data collected on the growth of the organisms under these circumstances revealed considerable variation in the total progeny after incubation of the microcultures even though all possible efforts were made to standardize the conditions. Attempts to transfer single amebae to test tube cultures failed to produce successful cultures, but it was found relatively easy to establish test tube cultures by transferring the microcultures to test tubes of S-F medium. Certain refinements were made in the microtechnique in the course of these experiments. It is suggested that microisolation of single trophozoites offers a good means of studying genetic and metabolic characteristics of Entamoeba histolytica.