Abnormalities in the vestibular reactions in schizophrenics have been reported in the literature. Pekelsky (1921) observed transitory lack of caloric response in two cases of catatonic stupor. Rosenfeld (1926) described four cases of acute catatonia in which on calorization a slow deviation appeared instead of the physiological response. Claude, Baruk and Aubry (1927) examined four cases of catatonia, eight of hebephrenia and one of dementia paranoides. In one of the catatonic cases no caloric or galvanic response could be elicited, and in the three others the reactions were diminished. The other cases showed normal reactions. The authors stated that a diminution of the responses could sometimes be observed in hysteria. Claude, Bourguignon and Baruk (1932) found the Chronaxie of the vestibular nerves greatly increased in patients with catalepsy, but normal after the disappearance of that symptom. Joo and Meduna (1935) stated that in old-standing cases of schizophrenia a lack or a considerable diminution of the vestibular responses could nearly always be found. Sercl and Vinar (1937) examined the vestibular reactivity in twelve cases of hebephrenia and thirteen cases of paranoid schizophrenia. The responses to rotation were normal in all cases. The caloric responses were found to be diminished or lacking. Lack of caloric response was more frequent in the hebephrenic than in the paranoid cases. Löwenbach (1936), working on Gjessing's cases of periodic catatonia, carried out quantitative investigations taking into account the latency period of nystagmus, its duration and the number of oscillations. He examined thirty cases, each of them repeatedly, and attempted to correlate the results of the tests with the periodical changes in the clinical picture. He found that shortly before and during periods of stupor the vestibular reactivity dropped, and that sometimes only a slow deviation could be elicited. The lowering of the frequency was due to the prolongation of the slow phase. The abnormalities were independent of the duration of the illness, and in some old-standing cases the response was normal. Sometimes a temporarily diminished reactivity was noticed which did not coincide with a change in the clinical picture. Löwenbach noted frequent and often abrupt changes in individual cases, and in some he observed transitory complete loss of reaction. Angyal and Blackman (1940) studied vestibular reactivity to caloric and rotatory stimulation in 58 unselected male schizophrenics and in 20 normal controls. The response to caloric stimulation was found to be considerably lowered, the rotatory response only slightly reduced. There was no correlation to the duration of hospitalization or to the conventional subtypes of schizophrenia. However, in a group of five patients with extreme apathy, indifference and poverty of mental contents the reactivity was particularly low. In cases with a periodical course the vestibular reactivity was distinctly lower during the catatonic periods than during the intervals. The same authors (1941) investigated the nystagmic reactions to caloric stimulation under the influence of alcohol, hyperpnoea and CO-inhalation in schizophrenics and normal persons. While in normals alcohol intake results in an increase in the frequency of the nystagmus, in schizophrenics a decrease was observed. CO, which normally has a depressing effect on the nystagmic reaction, produced an increase in schizophrenics. Hyperpnoea, while causing an increase in normals, had the opposite effect in schizophrenics. Freeman and Rodnick (1942) studied the amount of sway induced by rotation in thirty schizophrenics and in an equal number of normal controls. The patients were found to be significantly less reactive than the normal subjects.