Zimmerman and Burgemeister, who reported beneficial effects from glutamic acid treatment in cases of mental retardation, now study thirty-eight of their original sixty-nine cases in order to test the degree of permanency of their reported results. The present studies were made two and one half to three years after treatment had been discontinued. Of the thirty-eight patients, twenty-four had received one year of treatment and fourteen only six months. These

studies show that the group as a whole has retained almost one half the initial rise in intelligence quotient obtained under therapy (an average of 3.16 points as compared with an initial gain of 6.84 points). In the verbal portions of the tests, the amount of gain is of greater importance in determining the permanency of effect than is length of treatment. Performance test findings, however, favor length of treatment as a positive factor determining the degree of permanency.