Electrodialysis differs from ordinary dialysis in that an electric current is passed through the dialyzing cell and the impressed electrical potential hastens the removal of ions from colloidal material. Consequently, electrolytes are removed faster and to a greater degree than by ordinary dialysis. In the last twenty-five years electrodialysis has been used extensively in the study of the composition and purification of biological materials. Pauli (4) was the first worker to use this technique in the purification of proteins, whereas now it is a routine procedure. It has been applied extensively in the study of soil colloids and in general is the best method for the purification of lyophilic colloids. The technique has been used recently in other ways. Moore, Reeves, and Hixon (2) electrodialyzed normal and abnormal apple tissue in an attempt to determine the cause of spotting which occurs in Jonathan apples during cold storage. Neller (3) also used electrodialysis in a study of apple tissue. More recently Cooper, Paden, and Smith (1) used the same method in treating fresh samples of cotton, corn, and soy bean tissue in order to determine the ease of removal of various cations.