Physico-chemical factors affecting the behaviour and activity of Entamoeba histolytica.

Activity of individual trophozoites of several strains of axenic Entamoeba histolytica under different environmental conditions was measured by means of a newly devised method. Activity was found to be different between strains and corresponded to the degree of their pathogenicity. At low pH values amoebae moved further due to a straightening of their paths. A similar phenomenon was found in 1:50 cilution of pig bile. Bile was also found to induce an increase in the number of monopodial, "limax-like" forms in proportion to its concentration.