In certain cases the arterial spasm fails to affect the entire cortical surface simultaneously; some one trunk may be more pervious, and as afflux of blood may occur in its special field where certain impressions and motor innervations are stored, the result will then be that the function of the relatively well-nourished territory will be exalted. If it be a visual perception territory, sights, colours or luminous spectra will be seen; if it be an olfactory territory, odours will be smelt; if a tactile centre, crawling, tingling and cold sensation are felt; if a speech centre, cries, phrases, and songs may be observed. This explains the manifold epileptic aura, which is simply an isolated, exaggerated, and limited cortical function. The recurrence of the aura is readily explicable on the ground of the well-known physiological law that any nervous process, morbid or normal, having run through certain paths, those paths will be the paths of least resistance for that process to follow in the future. These conditions will be greatly exaggerated in proportion to the deficiencies in the associating tracts and will often, in turn, pervert these. The sexo-religious and other mental states of epilepsy often closely mimic normal mentation and serve to disguise the intense depth of degeneracy which epilepsy implies. In their explosive, unchecked character the morbid restlessness of the neurotic, hysteric, and criminal depend upon like brain disorder to that of the epileptic, except that consciousness is not involved, and with conscious acts are intermingled those preceding from the lower automatic processes described. Consciousness, however, is sometimes lost in part, whence frequently the defects so often noticed in the thoughts of the degenerates. The two following cases which have come to my notice illustrate the obliteration of the function of limited areas of the brain. A young lady, aged 22, of refinement and highly accomplished, was engaged to be married. One evening her _fiancé_ called; she failed to recognise him and he remained ever after a stranger to her. In every other respect her mind was seemingly normal. She died of tuberculosis. In another case a young lady, an expert stenographer, while riding her wheel, fell striking her head against a stone. She remained unconscious for some days, and was quite ill for three or four months. After her recovery she was much surprised to find that she knew nothing about her former employment, although her brain was perfectly normal in other respects. CHAPTER XVIII CONCLUSIONS