(_d_) Titubation, or staggering, is the inability to stand erect or walk straight because of impaired equilibrium. There is neither tremor nor ataxia present, and paralysis and anæsthesia are not necessary factors. It is distinguished from vertigo and dizziness by absence of subjective sensations of movement. Staggering may show itself in a general way or in the shape of latero-, retro-, or propulsion (disease of the internal ear, paralysis agitans). A well-defined variety of staggering is the wrongly-termed cerebellar ataxia. In this the patient, having disease of the cerebellum involving its vermis superior, stands with feet widely separated to increase his base of support; the body is bent somewhat forward, and the arms and hands are used as balancing-rods to maintain a sort of equipoise. In walking, this attitude is exaggerated, and if the feet be bare it will be seen that the toes are unconsciously clutching the floor for support; there is no outward jerk of the leg or stamp of the heel as in the ataxic gait, and closing the eyes does not aggravate the attitude or walk. Besides, if the extremities be separately tested, it is found that with closed eyes the patient can perfectly well place his fore-finger on his nose or one heel on the opposite patella (lying down). The proper term for the disorder is cerebellar titubation. Yet it must be remembered that titubation also occurs from disease of the oblongata and pons, from lesions of the base of the brain in general, and from alcoholic, etc. intoxication. In many cases titubation occurs in connection with vertigo or dizziness. (_e_) Inco-ordination more or less of the ataxic form often affects the muscles of articulation, phonation, and deglutition, giving to the symptoms dysarthria, dysphonia, and dysphagia. Dysarthria and dysphagia are probably often caused by lesions of the insula and subjacent white substance, as well as by those affecting the oblongata. There are two recent autopsies which would indicate that there may be a cerebral cortical centre for phonation laryngeal movements: in the ventral extremity of the right third frontal gyrus—a part homologous to the speech centre on the left side of the brain. In some cases, however, dysphonia and aphonia indicate a lesion of the laryngeal nerves or of the oblongata (nucleus of NN. x. and xi.). (_f_) Doubtless the internal muscular organs and the blood-vessels are frequently the seat of inco-ordinate or quasi-ataxic movements, but our present knowledge of these conditions amounts to very little.