Luys has suggested, therefore, that these intermediate stations of cerebral organs constitute peculiar centres in which crude nervous impressions sustain a primary elaboration before passing to the surface of the brain. Further, that the generation of emotions, which differs in so many respects from that of ideas, is especially connected with these centres as distinguished from the cerebral hemispheres lying above them. This idea is based on the following facts:

1st. The nervous masses in question are well developed in animals in whom the cerebral hemispheres, or organs of intellection, are comparatively rudimentary; and in these same animals, while little or no capacity for abstract reasoning exists, the instincts and feelings attain individuality and intensity.

2d. The emotions stand in much closer relation to sensation and movement, than do the operations of thought. The latter, indeed, necessitate immobility, and, if sufficiently intense, diminish the power of sensation; they seem to indicate a concentration of nervous action upon organs unconnected with motility or sensibility. On the contrary, movements of some kind are the first result of emotions, of which each is expressed by a characteristic gesture, and these increase in violence with the intensity of the feeling. A powerful emotion, as well as an absorbing thought, may, it is true, annihilate or transform sensation; but this is explicable by the fact that the strongest emotions are excited by ideas. Hence, on the hypothesis, the impression radiating downwards to the emotional centres from the cerebral hemispheres, would counteract a sensory impression radiating upwards from them, by a literal interference analogous to that observed in opposing waves of sound. But as the direction of the impression generating emotion coincides with that of the motor impulses, the latter would not be counteracted, but reinforced.

3d. Conversely, sensations of various kinds, transmitted to these centres from different parts of the body, are as effective as ideas in generating or modifying emotional conditions—often, indeed, much more so. The hypochondria of the ancients, the dyspeptic melancholia of the moderns, the infinite varieties of hysterical sensibility, are all well-known illustrations of this undisputed fact. The elastic consciousness of well-being that emboldens the volition of certain individuals, as distinguished from the timid apprehensiveness that constantly depresses the powers of others, is connected, not with any view of external conditions appreciable by the intellect, but with a vast multitude of vague bodily sensations, of which each alone fails to make a distinct impression upon consciousness.

4th. An impression made on one part of the sympathetic system is easily communicated to another, and to the ganglionic masses of the visceral plexuses, already described. Hence the rapid effect of many emotions upon the processes of digestion; hence the epigastric response to the emotion of fear, which led Bichat to localize this feeling in the solar plexus lying behind the stomach. In a precisely similar manner may the effect of emotion be distributed to the ganglionic nerves of the kidneys, uterus, and ovaries, leading to the flow of urine that terminates a paroxysm of hysteria, often suppressing menstruation, by contraction of uterine blood vessels, or causing an excess of menstrual hæmorrhage, from an excessive excitement of the ovarian nerves during the menstrual crisis. None of these effects are observed after a simple act of thinking, unattended by emotion.

5th. Probably on account of such an influence upon the vaso-motor nerves, the blood vessels, and, consequently, the processes of nutrition, the evolution of emotions is attended with much greater fatigue than is that of thought. The fatigue that may follow a prolonged intellectual operation is, moreover, distinctly localized in the head, and exists in various degrees, from simple inability for further attention, to decided sensation of weariness, or even pain. But the fatigue experienced after excessive emotion, especially if this be of a depressing character and accompanied by tears (which imply vaso-motor paralysis in the lachrymal glands), is generalized all over the body, and is, moreover, very much more often followed by headache, or by symptoms of cerebral congestion or anemia, than is the act of thinking, except in persons morbidly predisposed. When nervous exhaustion is observed after prolonged mental effort, one of two other conditions, or both, has nearly always co-existed, namely, deficiency of physical exercise, or presence of active emotion, as, ardent ambitions or harassing anxieties. In a few cases, the mental effort itself, by the afflux of blood determined to the brain, or the excessive activity imposed upon its elements, becomes an efficient cause of disease. But in these cases there is either an original imperfection in the organization of the nerve tissues, or the mental effort has been of that exceptionally intense nature of which none but a few minds are capable. Finally, in these cases, the resulting disease is seated in the brain or spinal column.

This latter remark is of great importance for our purpose; for it tends to show that diseases produced elsewhere within the range of the ganglionic system of nerves—as the menstrual hæmorrhage, that we are especially considering—must be due to some other nervous act than that of thought.

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 hæmorrhage. 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, invariably called the emotional centres into play; or, second, it might be said, that the original organization of the cerebral tissues in women was so imperfect, that a slight amount of activity was sufficient to exhaust them, and hence become a cause of hæmorrhage by the mechanism previously described.

Neither of these assertions is made by Dr. Clarke, but it is certain that one or both of them might be made in regard to a large number of women. To these, however, severe intellectual exertion would be injurious, not only if performed during the week of menstruation, but if performed at all. Nervous excitement during the inter-menstrual period, is quite as likely to be followed by pain or excessive hæmorrhage at the next menstruation, as if it had been sustained at the critical epoch itself. Nature generally provides for a portion of this contingency, by rendering such women little capable of mental exertion, and little ambitious for it. But, though they be kept in the most complete intellectual quiescence, the condition of these unfortunates is scarcely improved. Withdrawn from the serene and powerful movement of intellectual life, they are left to all the agitations of their ganglionic nerves; impressions, unfelt by others, raise storms of feeling in them, that actually ravage their nervous system; efforts that but slightly fatigue stronger organizations, are completely exhausting to theirs; health, indeed, is only possible to them while they may be sheltered from exposure, saved from exertion, and carefully screened from excitement and shock.

The method, therefore, suggested by Dr. Clarke for enabling young girls to master Latin and Greek without sacrifice of their health, seems to us to be addressed to the wrong element in the group of supposed causes. In the cases related by Dr. Clarke, there is nothing to show that the menorrhagia was occasioned by study during the week of menstruation, rather than during the three weeks that preceded it. Nor that even then, the true cause of disease was to be found in the intellectual exertion of mastering the school text-books, rather than in the moral excitement due to competition, haste, and cramming, or the close confinement necessitated by prolonged school hours, and unhealthy sedentary habits out of school.