In Florence flask cultures of the L.E.S. medium the average yield of Endamoeba histolytica, based on 20 experiments, was 1,530,000 per flask but was scanty in media made either from egg white or egg yolk.
The addition to egg white medium of cholesterol and 8 vitamins of the B complex group stimulated growth of E. histolytica to a point well over 1,000,000 amoebae per flask but was without effect on yolk medium.
Cholesterol alone or the vitamins alone in egg white medium had no effect on growth of E. histolytica.
The counts of amoebae obtained from medium enriched with the amino acids of casein hydrolysate and with the 4 purine bases were slightly higher than those from an unenriched medium.
Two commercial products of dehydrated egg albumin did not support growth of E. histolytica.
Ovalbumin, ovomucin and ovomucoid when added in combination to yolk medium showed some stimulating effect on the growth of E. histolytica.
In one instance an infusate of coagulated egg white plus the vitamins and cholesterol produced a fair crop of amoebae.