Cerebral hemorrhages, thrombosis and embolism are more or less intimately associated etiologically, pathologically and clinically. They all bear a rather definite relation to the general question of arteriosclerosis and may all lead to cerebral softening. Apoplexy is a term which was employed by Aristophanes, Demosthenes and Sophocles and has been in general use for centuries. It was known to Chaucer and was referred to in Shakespeare's works ("Henry IV"). It was studied very elaborately by Sydenham and many other early writers. Charcot and Bouchard in 1864 called attention to the relation existing between miliary aneurysms of the cerebral vessels and hemorrhages. In a study of the cerebral vascular lesions at the University College Hospital, London, Jones (_Brain_, 1905) found records of one hundred and sixty cases occurring during a period of sixty-five years. Of these, 123 showed hemorrhages; twenty-four, thrombosis; and thirteen were due to embolism. Thomas[196] states that: "The symptoms following acute vascular lesions of the brain, whether the process be the rupture of a vessel or its occlusion, are in many respects identical; and clinically it is often impossible to determine which process has been effective." He calls attention to the fact that in thrombosis the final closure of a vessel may occur suddenly and the symptoms develop with great rapidity. On the other hand, the rupture of a vessel may mean the escape of only a small quantity of blood and after an embolism the circulation is not always stopped immediately. In an analysis of 401 apoplectic attacks Thomas found no loss of consciousness in 202 cases, although it was interrupted or markedly disturbed in 199. Jones found a complete loss of consciousness in 47.7 per cent of 201 cases of cerebral embolism and a partial disturbance in sixty per cent. He reported consciousness affected in seventy-five per cent of his cases of cerebral hemorrhage and in 45.5 per cent of those of thrombosis. When it occurs it is usually not the initial symptom in his experience, being preceded by headache, vertigo, weakness in certain parts of the body, etc. An analysis of the cases of embolism reported by Virchow, however, showed a sudden loss of consciousness as the initial symptom to be the general rule. Gowers is of the opinion that an initial softening is a more common occurrence than hemorrhage.