Brodmann exhibited to the Psychiatric Society of Berlin two monkeys from whose brains he had removed the anterior and posterior central gyri. They had hemianopsia and loss of motor power in the hand. As the result of his experiments, he found that little impairment of function followed small excisions of the posterior central convolution, whereas a similar removal from the anterior central at once caused helplessness in the use of the hands (meaning, we suppose, the upper limbs), especially in the smaller joints. This powerlessness lasted for eight or ten days. In dogs, there is the same restitution of function, even after excision of both median gyri. Brodmann notes that after excision of the anterior central gyri there is much degeneration of the anterior tract, but comparatively little after a more extensive removal of the posterior central convolution.