The growth rates of Endamoeba histolytica and organism t were measured in media containing fractions of egg white as well as in stored egg white medium and the data compared with those obtained with fresh egg white medium. All media were enriched with vitamins and cholesterol.
Water insoluble and water soluble fractions of heat coagulated egg white obtained by Waring blender emulsification of coagulated egg white and by pouring raw egg white in to boiling Locke's solution failed to nourish the amoebae but supplied nutrients for organism t.
A diphasic egg white medium with the coagulum dispersed in the overlay failed with one exception to produce amoebae but produced uniformly good growth of organism t.
In a limited number of experiments, pullet egg white and egg white from spring and early summer hen eggs produced better crops of amoebae than were obtained from fall and winter eggs.
Oxygenation occurring in stored cotton stoppered medium resulted in loss of amoeba-producing properties.
In rubber stoppered stored medium in which residual oxygen was absorbed by pyrogallic acid there was no apparent loss of amoeba producing properties.
Ovomucoid diffusing into the oxygen free overlay of stored egg white medium produced good growth of amoebae in a wholly liquid medium.
Support was furnished for the theory that fresh egg white base probably acting in conjunction with organism t is concerned in the oxygen potential of the medium.
The growth of organism t was not appreciably affected by factors operating in stored medium thus indicating that the factors concerned were specific for the amoebae.
With the collaboration of Principal Biochemist Floyd S. Daft of the Division of Physiology.