Abstract
Entamoeba histolytica (National Institutes of Health strain 200) has been maintained in axenic culture through 50 transfers over a period of 6 months. The medium used is diphasic and contains a cell-free extract of chick embryo which is essential for growth. Inocula of 50,000 amoebas yield 150,000 to 200,000 organisms in 72 hours of incubation at 35°C. An extract prepared from boiled embryos supports growth equally well.