It has been demonstrated that Difco tryptone and Difco yeastextract, in low concentrations, accelerate growth of E. histolytica in cultures. The use of such growth-stimulating substances affords a possible method for the improvement of culture media.
The writer wishes to acknowledge her appreciation and indebtedness to Dr. R. P. Hall and Dr. H. W. Stunkard for assistance in preparation of the manuscript.