Galactose cataract in rats was first reported by Mitchell1 and confirmed by Yudkin and Arnold2 and Day.3 The problem was studied from several points of view by Mitchell and Cook.4 They recorded that galactose cataract develops most easily in young rats. The susceptibility of different strains was analyzed. The sugar content of the blood and of the urine, the influence of protein factors in the diet, changes in other factors and the stages in development and regression of the cataract were problems particularly considered. According to Mitchell and Cook a low protein ration shortened the time of development of the opacity in the lens. On the other hand, a high protein ration tended to retard this pathologic change. Bellows5 pointed out the inhibitory effect of 0.3 per cent cystine added to a low protein diet containing 35 per cent of galactose. Only slight protection of