On studying the behaviour of mental defectives one cannot fail to note that their deficiency is not confined to the intellectual or emotional plane. They are clumsy not only in their way of thinking and reasoning, but also in their bodily movements. Their muscular co-ordination and their manual dexterity are poor; they are awkward in their rhythmic work, and they rarely reach average standard at games. Their ocular movements show much the same shortcomings. They are sluggish at following a moving object with the eyes, they easily lose sight of the finger which they should fixate, and they are equally clumsy when they are called upon to look at will at an object in the fringe of their visual field. In some feeble-minded defectives of medium or even higher grades this inability may be clearly reminiscent of motor apraxia in other spheres of neuro-muscular functioning. More often than not precisely these patients are found to be particularly backward readers, able to decipher short words only and incapable of grasping the meaning of a printed sentence.