From the foregoing considerations, we believe, may be again inferred, first, that the radical difference which exists between the cerebral operations that result in thought, and those that accompany the evolution of emotion, probably depends upon the fact, that in the former central nervous action remains more or less localized on the surface of the cerebral hemispheres, while, in the latter, the great ganglia lying at the base of the brain, and hence nearer the vaso-motor centre, are called into play; second, that the effects of such action are more rapidly generalized throughout the nervous system, and, by causing the dilatation of the blood-vessels in the manner described, exhaust the central nervous system in a twofold manner, by a disturbance of its circulation, and by a direct depression of its nutrition, when the modifications of the circulation exaggerate the nutrition elsewhere. Repeated excitement and consecutive paralysis of the vaso-motor nerves, therefore, serve as the most efficient means of draining off the force of the cerebro-spinal nervous system. And it has been seen, that a depression of its power is followed by an exaggerated and irregular activity of the ganglionic system, to which are due most of the phenomena observed in hysteria and in ordinarily nervous women. These are in many respects different from those observed in men suffering from so-called nervous debility, for the reason, that in them the ganglionic system of nerves is less prominent, and its irregularities of action therefore less marked, when the control exercised by the cerebro-spinal system has been diminished. If the vaso-motor centre of the brain is only influenced when the ganglia at the base are called into activity, and if their activity coincides with emotion, and not with thought, whose organ is much more remote, in the cerebral hemispheres, it should follow that emotion, and not thought, should most easily influence the vaso-motor centre, and be followed by peculiar modifications of the ganglionic system and of the circulation. This supposition is confirmed by the occurrence of many vaso-motor phenomena that commonly follow emotion, but are rarely observed after even prolonged thought. It is not, therefore, stimulation of the intellect, but excitement of the feelings, that can be shown from physiological data to have an injurious effect upon the vaso-motor nerves of the uterus, or the ganglionic nerves of the ovaries, or, in other words, can be concerned in the production of uterine haemorrhage. To be just, however, it must be admitted, that still another view is possible. For it might be affirmed: first, that in women communication of impressions between different parts of the nervous system was so rapid, that the limitation of activity to a particular part of the brain was impossible; in other words, that the distinction between thought and emotion was effaced, because any action set up at the surface of the cerebral hemispheres,