recurrence of the catarrh, and immediately the mental symptoms recurred also; his hallucinations returned. On the cure of the bladder trouble the mental trouble permanently disappeared.

Niemeyer relates that he "treated a very wealthy man for chronic gastric and intestinal catarrh, who, during the disease, thought he was near bankruptcy, and left unfinished a great building he had begun because he thought he had not sufficient money to continue it. After spending four weeks at Carlsbad, his old strength and feelings returned, he finished his house with great splendour, and has been well ever since."

Two cases have been recorded by Dr. J. A Campbell, and I have had two under my own care, in which local abdominal disease (ulcer of the intestines in three of the four cases) was associated with insanity, and the manifestations of the insanity had direct relation to the bodily disease. In each case the patient had the delusion that his bowels were entirely obstructed, and that nothing ever passed through him, and persisted in this delusion in spite of daily evidence to the contrary. It is very significant that Dr. Campbell's patients were brothers, a fact which speaks very strongly for the existence of a previous tendency by heredity to insanity, a tendency which was converted into actuality by the stress. of the bodily malady, and received from the latter its local colour.

CHAPTER X.

THE CAUSES OF INSANITY (Continued).

Indirect Stresses of External Origin.

THIS class of indirect stresses arise from the action on the higher nerve regions of the circumstances in which the individual is placed. It has already been explained how conduct, the aggregate of the movements of the organism as a whole, is actuated by the highest nerve regions; each phase of conduct depending on the action of a special portion of these regions. And it has been explained how conduct is determined, both from moment to moment, and in its longer excursions, by the impression that is made upon the organism by circumstances. The impressions that determine the minor features of conduct arise from limited portions of the circumstances, and those that determine more important phases arise from larger and larger aggregates of circumstances. The particular moment and place at which it becomes necessary to touch a horse with the whip are determined by the particular impressions made by a limited group of circumstances—the pace and disposition of the horse, the lie of the ground, or the position of surrounding objects. The choice of the time and occasion of setting out on the journey is determined by a larger group of impressions, made by a larger group of circumstances: by the need of visiting a certain person, at a certain distance, for a certain purpose. The resolution to "set up" a carriage is determined, again, by a larger group of impressions, proceeding from a wider group of circumstances: by the recurrence of

needs of travelling certain distances in certain times to supply certain needs, by the general state of prosperity, and so forth. In each case it is the complex impression made by an aggregate of various circumstances that determines the conduct; and the impressions, which are received proximately by the special sense-organs, and are co-ordinated and combined in the lower and intermediate centres, produce their special effect in determining conduct only when they impinge upon, and alter the disposition of, the highest

centres.

It is the normal function of the impressions made by circumstances to impinge on and to produce an alteration in the highest nerve centres. It is easy to understand, therefore, that if, from any cause, the impressions are excessive in intensity, the alteration that they produce in the highest nerve regions may be excessive. Normally, this alteration is limited to the setting in activity of centres already organized or in process of organization, and to producing new combinations of centres, by forming new connections between them, in the way indicated in the opening chapters. Speaking in terms of molecules, the function of the impressions made by circumstances is to produce discharge of certain extensive groups of molecules, and re-arrangement of certain other groups. Now, supposing that the in-going wave produced by the impression is of undue volume and intensity, it is easy to understand that the discharge of the molecules might be continued to complete disorganization, and the rearrangement might be so extensive as to result in confusion. Either of these conditions, and à fortiori a combination of both, would be sufficient to dissolve the organization of the highest nervous regions, an organization which, as we already know, is feebly compacted, unstable, and easily disarranged. The highest nerve regions, whose function it is to produce those elaborate and prolonged combinations of bodily movements in adaptation to circumstances that we call conduct, are not only of feeble stability, and loosely compacted organization, but they are, as we have

seen, far less definite in their limitations than the lower centres. When a lowest centre is destroyed, a certain part of the body, a muscle or a limb, loses its function completely, while adjacent parts suffer little or not at all. When a middle centre is destroyed, a certain part of the body, a limb or part of a side of the face, suffers much, but retains some function, and the adjacent parts-other limbs or the rest of the side of the face-suffer somewhat. In the highest centres the delimitation is still less sharply defined. When one of them is destroyed, the whole body suffers somewhat, though certain parts suffer more than other parts.

As an accompaniment of this absence of strict delimitation of the function of the highest nerve centres there is a similar absence of delimitation of their structure. They are not rigidly defined, but merge into one another on all their confines. An excessive discharge started in a lower centre does not as a rule spread far. An excessive discharge started in a middle centre spreads down to its subordinates before it begins to spread laterally to its equals in rank; and hence we find that an epileptiform seizure, beginning in the hand, spreads to the arm before it begins to involve the face or leg. But an excessive discharge, beginning in a highest centre, has as much tendency to spread laterally to its coevals, the other highest centres, as to spread downwards to its inferiors. Hence we find that, when a very voluminous impression is made on the organism, a very widespread wave of discharge spreads all over the highest regions, and arouses in a nascent form a vast complex of activities and of slumbering forms of expression that had previously been registered there. Such a widespread wave of discharge is accompanied by a mental state, a mental state consisting of a vast complex of indistinct confused memories of multitudinous activities and impressions previously experienced; and this flood of vague memories is termed an emotion.

The physical accompaniment of thought is, as we already know, the formation of new connections between centres. Such a process is in its very nature orderly and little prone

to excess. But the physical accompaniment or basis of an emotion, which is a diffused tumultuous wave of general discharge from many widespread regions, can, it is obvious, easily become excessive, and, when excessive, tends much more strongly, by excessive exhausting discharge, to produce disorder, than does the orderly, localized and gentle process of forming connecting channels between one centre or region and another. Hence the impressions that tend to produce disorder in the highest nerve regions are those whose access is attended by emotion, and those impressions which merely are occasions for increase of intellectual activity are not of a dangerous character. It is, therefore, in emotion-producing impressions that we seek those sources of stress that endanger the stability of the highest nerve regions, and rank as causes of insanity.

The inferior potency of this class of indirect stresses as causes of insanity is seen in this; that, while the direct stresses will, if sufficiently potent, disorder the most thoroughly hale and stable nervous system sufficiently to produce manifest and unmistakable insanity; and while the internally arising indirect stresses, which are harmless to nervous systems of great stability, will, in those of average stability, produce some disorder,-the indirect stresses are powerless, even when of great intensity, to produce insanity in a person of average nervous stability. In order to occasion insanity, the indirect stress must act on a nervous system which is hereditarily constituted with stability distinctly inferior to the normal.

The stress on the highest nerve regions will be severe in proportion to the volume and intensity of the emotion; and the character and magnitude of the emotion will depend on the character and gravity of the circumstances which give rise to it. Different sets of circumstances produce different emotions, of which some are attended by far greater stress than others, but common to them all are the features that— (1) The greater the emotion, the greater the stress; and (2) the more sudden the emotion, the greater the stress. The