consensus, this co-operation of all the vital forces of the nervous elements, laid under requisition in their totality, emerges a new notion, of which we have, so far, but sketched the genesis-a notion of a whole, which is, in a manner, the synthesis of all our mental activities; that is to say, the notion of our own personality. Upon this subject we are now about to enter.

CHAPTER III.

GENESIS OF THE NOTION OF PERSONALITY.

THE notion of our essential personality-that notio princeps around which all the phenomena of our mental activity revolve—arises, as we have already hinted, from the intimate contact between the sphere of psychical activity and the intellectual sphere. It is a complex phenomenon, which undergoes development; a true physiological process which has its phases of evolution, its own mode of origin, its manifold conditions on which its life and endurance depend, and its passing moments of disturbance during which it may be eclipsed and momentarily disappear.

The elements of the vegetative and sensitive sensibility of the living organism* enter as primary factors into the genesis of the notion of our personality, and the effective participation of the elements of the sensorium completes and perfects it.

We have already shown, indeed, that by means of the nervous system, the elements of sensibility may be directed and drained away from the regions where they originate, and transported to a distance into the plexuses of the sensorium, which are the common reservoir of all the partial sensibilities of the organism. * See p. 105, &c.

We have shown, also, that all the sensitive regions of the human organism find in this sensorium a symmetric point vibrating in unison with them, and that by this means our individuality in its totality, sensitive fibre by sensitive fibre, is transported to the plexuses of the sensorium where it is manifested.

The result is, that these plexuses enclose in their minute structure our living and feeling personality all complete, the sensitive elements which constitute it being fused into an inextricable unity. They serve as the basis of its manifestations, they unite to bring it to birth, they vivify it incessantly by their own energy, and thus, by always maintaining its vitality and sensibility, they keep it in perpetual contact with the excitations of the external world, which every instant flow in.

Through this subtle mechanism, the notion of our personality comes to life in us, being necessarily derived from a series of regular phenomena of the life of the nervous system. All the diffuse sensibilities of the organism, each in its own key, are, as we see, united in the plexuses of the sensorium, and thus become the primary materials for its formation.

As a natural consequence of this physiological evolution, from the very fact that the perceptive regions of the sensorium have given it birth, it results that it comes into direct contact with external impressions, and is inevitably associated with all the nervous excitations these develop in their train. It is constantly informed of these, is constantly conscious of all that passes, of the different characters and degrees of intensity of these excitations. It is impressed, it is moved, it is sorry or glad according to the various modes in which

the elements of the sensorium, which are its natural basis, are themselves impressed by the incident stimulations.

Thus the phenomena of conscious perception, looked at from the physiological point of view, come within the natural limits of regularly accomplished nervous functions. There is a vital operation, a normal process, which originates and is developed by the mere fact of the co-operation of all the vital forces of the nervous system laid simultaneously under contribution. Like all the grand functions of the economy, the process on which the notion of the conscious personality depends, only lives and is maintained by the incessant concurrence of all the nervous apparatuses which take part in it; and this notion only becomes paramount and stable in itself by the continual operation of the organic mechanism by means of which it is developed.

If an interruption in the arrival of external sensitive impressions in the sensorium occur, special disturbances will appear, and will reveal themselves in a very characteristic manner. Thus we meet with certain patients who, when affected with anesthesia of the lower limbs (certain forms of locomotor ataxia), say that when they are lying in bed they can no longer feel their limbs; they do not know where their legs are. They are no longer conscious of that portion of their personality which is constituted by their inferior extremities.

When the currents of blood which carry life to the cells of the sensorium are suspended, another order of very significant phenomena is developed. There is a sudden arrest of the working of the living machine. Everything stops at once; everything imme

diately remains suspended. The perceptive regions of the sensorium, struck, in a manner, with asphyxia, are all at once deprived of the property of feeling excitations from the surrounding medium; they remain torpid, inert, and the human personality ceases at the same time to be conscious of the things of the external world, of which it thus loses the knowledge (syncope, fainting, epileptic vertigo).

Again, if the plexuses of cells in the cortical substance, which are to a certain extent isolated as regards the arrival of blood in their tissue, as they are as regards dynamic activity, receive at a given moment more blood than is their wont, and thus assume a condition of morbid erethism, the regions of conscious personality remaining comparatively unaffected, a strange phenomenon will result, in which the individual, without having lost consciousness of external things, will be almost passively hurried away by the automatic activity of certain regions of his brain, which will urge him to utter words and to commit extravagant actions, and this in an irresistible manner, and quite without the agency of his will.

These facts lead us to the opinion that the phenomena of conscious perception, like true physiological processes, are decomposable by analysis into successive phases, and that they only develop and come to perfection through the integrity of the different media which give them birth.

From this point of view they are quite comparable to the phenomena of hæmatosis, which take place in an incessant and continuous manner only by means of the effective co-operation of a series of