PHYSIOLOGY OF THE VESTIBULAR APPARATUS 271 at constant velocity, the cupola on the crista will return to rest and there will be no sensation of rotation and no nystagmus. If the rotation is suddenly Fig. 150. Rotation chair. Posterior Left Horizontal AmpullaJ 11 to*™** Flow of Endolymph pulls eyes to left Beginning of Rotation to Right Posterior Right Horizontal Canal Ampulla **** Ampulla B Horizontal Canal Endolymph ^ Anterior ~^ X pulls eyes to right Nystagrtws — ^__________ to /eft ^ results End of Rotation to W>* Fig. 151. Diagram of flow of endolymph in horizontal semicircular canals in rotatii standing above and in front of the patient, is asked to visualize what is taking plat beginning and also at the end of the test. The patient is looking towards the bottc rizontal semicircular canals in rotation test. The observer, asked to visualize what is taking place in the canals at the : patient is looking towards the bottom of the page.