YOUNG rats of the Wistar Institute strain aged five to six weeks and weighing 70-100 gm. were fed on the Gillman diet1. This consisted of liberal quantities of a thick mealie-meal porridge and fermented cow's milk. Animals were killed after they had been on this diet for four and a half and six months. All, except two in the latter group, showed an abnormal bromsulphalein retention in the serum; but the serum proteins, thymol turbidity, thymol flocculation and colloidal gold tests were within normal limits.