To this vegetative function, nevertheless, it is necessary to assign an aliment, an organ, a mechanism. Now as yet we know of only two material forms of assimilative activity, the one semi-liquid for digestion, the other gaseous for respiration. The aliment of sleep would be, as opposed to this, an ethereal matter, or, if we wish, a dynamic form, susceptible of being accumulated and of being transformed in various ways. At first sight, no doubt, it seems difficult to accept a sthenic aliment, without a ponderable substratum, and it sounds a little strange to seek in the phenomena of wake and sleep "an assimilative group the object of which belongs to the ambient dynamism," in other terms, "a functional activity," which should be influenced by the condition of the alimentary source—that which would give at the same time the explication of the fact, that, in a general way, the two phases of wake and sleep are related to the planetary periodicity of day and night, summer and winter. Let us, however, follow M. Sergueyeff in his interesting researches, where the scientific spirit does not cease, at any rate, to sustain him.
In his theory the cerebro-spinal system is no longer the organ, as it is in the theories of congestion and anæmia; but it is rather the so-called sympathetic elements, the ganglio-epidermic system, of which the imperfectly known functions rightly require to be explained. Struck with the insufficient reasons given of the phenomenon of caloricity resulting from the section of a sympathetic nerve, or from the obstruction of a ganglion, M. Sergueyeff has been led to assume an action of the great sympathetic, different from the vaso-motor action. He does not hesitate, in order to explain the caloricity, to admit into physiology the principle of the mechanical equivalence of heat. He endeavors to prove, by an ingenious argument, that the heat which is produced after the section of the sympathetic nerves, finds its immediate origin in the arrest of a nervous centripetal movement; that this arrested movement owes its existence to dynamic condensations, to which certain organs of the ganglionic system are adapted, being endowed with a condensatory capacity; and finally that in the normal state the movement represents, not an expenditure of energy, but a contribution, that is to say, it is a movement of a trophical character.
The sanguineous condition of the brain remains to be considered; but the difference in this respect between wake and sleep, would be purely distributive instead of being quantitative. Schiff has remarked that white rats deprived of their cerebral lobes and corpora striata sleep and wake; which leads us to think that the phenomena of cerebral irrigation are consequentials, and not essentials, of wake and sleep. In short, these two alternating phases serve in turns as chief moving causes for the vaso-motor excitation which differences, in one or the other period, the sanguineous condition of this or that medullar locality.
We cannot follow the author in the special study he makes, first of the sensitive nerves and the motor nerves, then of the "cerebral activities" in the conditions of wake and sleep. It would be laborious to disengage his psychological doctrine from the long discussions which envelop it, and which, well carried out as they may be, do not always allow it to appear with as much distinctness as could be wished. We will note only the care that he takes to restore the psychic initiative, contrary to the theories most in favor to-day. He supposes a prefunctional movement of the sensitive nerves, in order to determine the sensorial impression; "attentive volitions" in order to explain attention, voluntary or involuntary. According to him, the physiological phenomenon which necessarily corresponds to sufficient attention, that is to say to the laying hold of an object by consciousness, can only be a volitional nervous movement. He remains convinced that "the cells of the brain must project incessantly in certain of their afferent fibres centrifugal influxes which tend to meet with perceptive images"; and feeble and involuntary as these influxes may be, he ranks them nevertheless in the somewhat mysterious category of so-called attentive volitions. These are not reflexes, but automatic movements. And definitively, every act of attention belongs to the category of volitional movement, be it involuntary or voluntary; or in short, "attentive volition exists prior to its voluntary strengthening."
As to the revival of images, it is necessary to admit the intervention of a previous tendency to association. The difficulty remains then to know how we are to be able to keep these images before the consciousness, in order to apply our attention to them, and what secret cause has power to arouse the signals, the nervous movements, which present them to it. The author resolves the difficulty by accepting, for cases of intentional reviviscence, ideo-motor volitions, to which he attributes a considerable rôle; their intervention distinguishes precisely, says he, the active memory from the passive memory.
In reality, for M. Sergueyeff the consciousness is not, as we have said, a simple result of the image, an epiphenomenon; it is permanent (thus he affirms that we always think, that we always dream); the Ego, the We is for him an irreducible factor. This way of looking at things has evidently influenced the choice of his terminology, more than it has vitiated his analysis, and its conclusions, moreover, he has not put down to the credit of any system of metaphysics whatever. Far from having exhausted the matter of his book, which is replete with criticisms and facts, I have hardly sketched its outlines, and I should be his false interpreter if I did not recall, in conclusion, the hope strongly expressed by himself, that the great assimilative work of an imponderable aliment reserves for us many other solutions beyond that of the phenomena of wake and sleep. "Though it may be," says he to his hearers, "that in all the recent words I have uttered, the truth shines only by a spark, do not disdain this spark, gentlemen. May one of you receive it within him, for it can, I have the confidence, by a more powerful breath than mine suddenly increase, like a polar aurora, and illuminate unbounded horizons."
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We now come to a book of less scope, rudely constructed perhaps, but very instructive. As indicated by the title chosen by him, La Psychologie de l'Idiot et de l'Imbècile,[87] Dr. PAUL SOLLIER has attempted to draw the portrait of the idiot and the imbecile in general; which I sincerely approve of persuaded as I am that we shall find profit in sketching generic types and in tracing the composite photographs of social individuals grouped in various ways, in order to establish on solid basis a "natural history" of societies. The novelists have approached this difficult enterprise at random; it is for the psychologists to direct it with a method more sure and a tact not less delicate.
[87] Alcan, publisher.
Idiocy is not always congenital; the lesions which produce it are extremely varied and do not consist by any means in a simple arrest of development. In short, idiots form a very diversified clinical group; and here was the first difficulty necessary to overcome in order to write their psychology. Profiting by the insufficient definitions that authors have given of idiocy, M. Sollier thinks he is able in his turn to define it as "a chronic cerebral affection with varied lesions, characterised by troubles of the intellectual, sensitive, and motory functions, going possibly as far as their almost complete abolition, and which assumes its special character, particularly in what concerns intellectual troubles, only in the youthful age of the subjects it strikes." Then, discussing the proposed classification, he stops to form three categories, which he connects with the intellectual development, for which attention serves him as the touch-stone. They are: (1) absolute idiocy—complete absence and impossibility of attention; (2) simple idiocy—feebleness and difficulty of attention; (3) imbecility—instability of attention. These differences in the state of attention (we recognise the fruit of the excellent teaching of M. Ribot) separate with sufficient clearness the imbecile from the idiot: the latter remains extra-social, the former becomes anti-social. M. Sollier, for whom the imbecile, let us say in passing, is an exceedingly disagreeable personage, follows out throughout the whole of his book this distinction, which seems to us one of the most curious and the most piquant aspects of it. How many people in the world border on imbecility, without belonging clinically to this type, and maintain the mischievous rôle of destroyers and marplots!