old ideas takes place instantaneously, when individual spontaneity and personal originality burst forth in the most pronounced manner, and when, in fact, the man appears with the cerebral temperament which specifically characterizes him.

As maturity approaches, the automatic energies of the cells become gradually less intense. Their sensibility is already dulled in consequence of the multitude of impressions which have affected them in turn; their appetite for unknown things is less intense"; it is their period of beginning saturation. The thirst for knowing and registering new facts calms down by degrees, and the mental forces then concentrate themselves for the regular classification of acquired riches, the methodic grouping of facts belonging to the past, and the calling into activity of the materials long ago accumulated, which serve for the building up of our judgments, the formation of our thoughts, the maturation of our reflections—so that if the human brain has already lost something of its freshness, and the juvenility of its manner of feeling, it has gained, per contra, the fruits of acquired experience. It knows and automatically expresses what it knows; and these different modes in which the human personality reveals itself as regards its external manifestations, represent the true synthesis of all the mental activities in their full expansion.*

* It is curious to observe practically, in every-day life, how variable the degree of the automatic energies is in different individuals, as regards the rapidity of the transmission of nervous excitations to the brain and of the consecutive reactions. We know indeed how many individuals there are who, as it is said, have their understandings slow, sluggish, and hardly permeable by the stimulations of the external world, which are radiated towards them. Every one knows that a great number of people exist, who, although very intelligent as regards a certain class of ideas, are incapable of appreciating the

The effects of progressive senility are marked by insensible gradations in human brains, by a slow and gradual enfeebling of the automatic activity of their elements.

That failure of appetite for, and curiosity about, new things, which is already marked in the preceding stage, becomes more and more distinct. That deadening of the sensibility, which expresses the complete saturation of the elements of the sensorium and their incapacity for maintaining a condition of erethism, takes more and more significant forms. The human brain experiences the need of prolonged repose; the ardour of the grand struggle for life becomes painful to it. A retreat is sounded from a great number of social careers. it is that that period of inactivity which inevitably awaits each individual, as regards the social part he has played, physiologically expresses the slow and gradual wearing out of the energies of automatic life, which by degrees cease to vibrate, and betray by their slackening the progressive dulling of the sensibility of the cerebral cell.

Thus

In proportion, then, as sensibility grows languid, and the faculty of erethism loses its energy in the elements of the sensorium, the external manifestations of the life of the brain undergo a parallel retrogressive movement. Repose and silence insensibly invade them. The field of the ideas and sentiments grows narrower; intellectual spontaneity becomes languid, and verbal expression, and association of two incongruous ones. They but very slowly comprehend facetiæ and plays upon words, and in conversation, when a play upon words has been made and every one has laughed, they alone hang fire, and show by a tardy burst of laughter that the hilarious effect has at last been produced upon them also.

conversation, dried up at the fountain-head, cease to be interesting and endowed with a spontaneous character. The man who has nothing to say, who has but a few notes of his personality to set vibrating, speaks no more or says but little, at least if we do not take for original conversation those vapid phrases that men think themselves obliged to exchange, when they are in each other's company, and of which the inanity, to some extent reflex, only covers the absence of ideas and sentiments.

Thus it is that, through the necessary connections which unite all the zones of cerebral activity, the manifestations of senility by degrees gain ground in the psycho-intellectual spheres. The mere fact that there are regions of the brain which have primarily been struck with stupor and histological degeneration, causes the same retrogressive processes to radiate to a distance, and, through secondary lesions, inevitably to produce the symptoms of senility and more or less progressive dementia.

CHAPTER VI.

FUNCTIONAL PERTURBATIONS OF AUTOMATIC ACTIVITY.

IT is in the series of morbid phenomena peculiar to mental diseases that the processes of automatic activity generally present themselves with their most significant characters of intensity, and in the most diverse forms.

It is, in fact, the automatic activity of the cerebral cell that always more or less comes into play, in general or partial delirium, and in irresistible impulse, being everywhere essentially active, and everywhere present. It is always this that reveals itself with those characters of irresistibility, and that evident freedom from voluntary action which are its special characteristics.

Thus general delirium, with that exuberance of thoughts which clash and associate in the most unexpected manner in the brain of the patient, is the highest expression of the automatic activity of the cerebral cells in a condition of irrepressible erethism. It is enough to have seen patients at this period of extreme over-excitement, to recognize the fact that the will is powerless to repress the disorder; that the very elements that constitute human personality are themselves in disarray; and that in this agitation these

incoherent words, these sonorous explosions to which all the cerebral elements contribute in so unconscious a manner, we cannot fail to recognize the tumultuous expression of the forces of normal energy, unchained and hurried into a very whirlwind of morbid overactivity.

In some forms of partial delirium, we see patients less vehemently hurried along in spite of themselves; incessantly delirious on certain points, conceiving the same delirious conceptions, always repeating the same phrases, without perceiving that their ideas are in complete discord with reality. Thus they say they are ruined, robbed by every one, poisoned; and even if anyone should reason with them, proof in hand, respecting the folly of their apprehensions, and reassure them in a thousand ways, the automatic activities of their brain are so set in a false direction that they incessantly return to it, just as a contracted member on being extended will resume its former position. They are perpetually complaining, they incessantly repeat the same phrases, the same vague apprehensions, and unconsciously fall back into the same ruts followed without conviction, without participation of their conscious personality, merely by dint of the automatic forces. of their troubled mind.*

In other circumstances automatic activity is exercised in a morbid manner within a comparatively limited circle, and only engages certain zones of the cortical substance, the others remaining comparatively unaffected; as we see for instance, certain cutaneous

* See Billod," Annales Médico-psychol.," 1861, p. 541. Lesions of Association of ideas; fixed ideas.