Under the influence of anesthetics, particularly of the so-called brain-stem anesthetics, various types of ocular rotation (heteronymous and homonymous rotation) occur. Stimulation of the cortical oculogyric centers may produce, besides conjugate deviation in a horizontal or vertical direction, a slight rotation (most frequent reaction: rotation of the opposite eye towards the side of stimulation). Tonic effects of the cortex upon the position of the eyeballs in regard to rotation could not be found. Elimination of the cortex plus subcortical ganglia in front of the midbrain produces moderate degrees of rotation, but not such high degrees of rotation as are observed under the influence of anesthetics. After unilateral labyrinthectomy, rotation to the side of the operation is more marked on the opposite side than on the homolateral eye; this rotation may outlast the spontaneous nystagmus. A similar homonymous rotation may be produced by a unilateral lesion of the vestibular nuclei, suggesting that disturbances of the equilibrium between the vestibular nuclei of the two sides may play a part in the genesis of homonymous rotation observed in barbiturate anesthesia. Ocular rotation is still produced by brain-stem anesthetics such as dial-urethane in mid-brain animals. The ocular rotation produced by anesthetics is only partly due to depression of prosencephalic and dien-cephalic activity and partly to direct action upon the lower centers. Separation of the mesencephalon from the rhom-bencephalon in normal as well as in mid-brain animals diminishes the rotation produced by barbiturates, but does not abolish this rotatory effect; this indicates a direct action of the anesthetic upon the midbrain, besides the action upon rhombencephalic supranuclear centers.