1.A medium consisting of Locke solution containing one part to seven of inactivated human, horse, or rabbit blood serum has been found very efficient in the cultivation of Endamoeba histolytica. The best results were obtained when inactivated human blood serum was used.
2.The excellent growth of Endamoeba histolytica obtained in this medium demonstrates that coagulated egg or blood agar slants used as a sub-stratum, are not essential for the growth and development of this species, and that neither egg or blood are essential as a part of the food supply of this species.
3.In this medium Endamoeba histolytica has remained alive and motile for a period of eleven days and successful transfers have been obtained in the medium after a period of eight days. The best results in transferring cultures are obtained by making transfers every twenty-four or forty-eight hours.
4.Transfers of Endamoeba histolytica, in this medium, made at intervals of twenty-four and forty-eight hours, have been continued for over three months in this laboratory and the amoebae have not changed in morphology or in their capability for reproduction during this time.