in their constituent elements, whether in the peripheral or central regions, the processes of attention are, at the same time, disturbed and arrested in their regular evolution.

Thus, when it is the peripheral regions that cease to be in their normal conditions of receptivity, when the sensorial apparatuses are not adjusted in the required direction-when, for instance, certain sensorial plexuses are struck with anesthesia-the unperceived and unregistered excitations from the external world are practically absent as far as the sensorium is concerned.

Thus, physicians are well aware how indifferent all anæsthetic individuals are to oscillations of temperature in the atmosphere in contact with their bodies; how little attention they give to what directly touches them, yet only produces in them a confused impression; how certain individuals with well-marked myopia have a vague and blinking mode of looking at those things in the surrounding visual field which they do not see, and to which consequently they pay no attention; how easily the deaf are distracted, only following with much trouble the series of ideas brought before them ; how in a great number of individuals attacked with mental diseases the systematization of certain forms of delirium has no other cause than a sympathetic irritation, or sensitive disturbances radiating from the peripheral regions which alone attract their attention. (Phenomena of hypochondria.) We know also, that when these same regions are excited, and have arrived at the pitch of pain, they keep the faculties of attention in the sensorium in a permanent condition of erethism. Every one, indeed, knows how vehement a

reaction the painful spot has upon the sensorium when we suffer in any point whatsoever of our sensitive territory; how completely it absorbs all our attention; and how profoundly its painful radiation jars upon our conscious personality, which is forced to pay unbroken attention to what is occurring.

In other circumstances it is the central regions that are engaged, and therefore place an obstacle in the way of the regular perfection of the processes of attention.

Thus, in idiots and imbeciles, the state of imperfection of the nervous system, either of the peripheral or central regions, renders them dull in perceiving, regularly, impressions from without. Their senses are dulled, their sensibility obtuse, and thus they are capable of but a slight degree of attention. They see badly, hear badly, feel badly, and their sensorium is in consequence in a similar condition of sensitive poverty. Its impressionability for the things of the external world is at a minimum, its sensibility weak, and consequently it is difficult to provoke the condition of physiological erethism necessary for the absorption of the external impression.

Thus it is that defect of attention is the rule in these special forms of mental degradation, and it is not without reason that Esquirol has connected the inaptitude of idiots for education with their defect of attention.*

* "Imbeciles and idiots are deprived of the faculty of attention," says Esquirol. "I have repeatedly made this observation with regard to them. Wishing to mould in plaster a great number of insane persons, was able to do so even with furious maniacs and melancholics; but I never could succeed in getting imbeciles to keep their eyes closed long enough to apply the plaster, however good the intention with which they went to work. I have even

In all forms of mental disease the faculty of attention becomes gradually weaker, and presents, according to the intensity of the morbid process, different and fatally progressive modifications.

In a general way, in persons with hallucinations, individuals attacked with acute or chronic mania, etc. etc., the forces of attention cease to take effect, the phenomena of the external world no longer produce in the sensorium anything more than an abortive impression. Morbid excitations are developed locally in the very regions of subjectivity, which become erethised of their own accord, and thus virtually become an insurmountable barrier between the individual and the surrounding medium. The patient, thus shut up from external sounds, a stranger to everything that passes around him, lends but an inattentive ear to the things of the external world. He lives, as people say, in himself, upon remembrances of the past, and upon his habitual delirious conceptions. Days pass away, the world goes by, events succeed around him, he no longer pays any attention, and the progressive indifference and invading apathy which manifest themselves in him, attest the gradual exhaustion of the vital forces of his mental activity.*

seen them cry because the mould of their heads has not succeeded, and several times vainly make the attempt to keep the pose that was given them, not being able to keep their eyes shut more than a minute or two." (Esquirol, Tome I. p. II.)

* There are circumstances in which, in the case of insane patients whose intellectual faculties are not as yet quite extinguished, we see certain sharp and unexpected external excitations come in to produce a happy modification of their mental condition and provoke in them some manifestations of attention. Thus Vigna has reported the history of certain individuals, who though apparently incapable of the simplest reasoning, when brought into the presence of a person who overawed them, a magistrate for instance, were much excited by the influence of the new circumstances in which they were placed, and then

produced the elements of a regular defence, and thus succeeded in preventing a judgment of interdiction. ("Annales Médico-psychol." 1871, p. 17.)

Baillarger has similarly noticed that in certain patients with hallucinations, vivid and sudden impressions may arrest the morbid working of their brains and induce attention to what is going on around them. "At the moment of the arrival of the physician," he says, "hallucinations disappear. They cease to hear voices; but one has scarcely left them before they fall back into their false conceptions." (Annales "Médico-psychol." 1845, vol. vi. p. 185.)

CHAPTER II.

CONSTITUTION OF THE SPHERE OF PSYCHO

INTELLECTUAL ACTIVITY.

WHEN once the external excitation is disseminated through the plexuses of the cortical substance, and incorporated in the sensorium, developing in it the specific energies of the cerebral cells that have received it, this new medium itself comes into play, and reacts in the direct line of its latent capacities.

The sphere of psycho-intellectual activity then exhibits all its natural riches, all the stores of its awakened sensibility. It is suddenly thrown into agitation, reacts, and thus develops the marvellous capacities with which it is fundamentally endowed. This new medium which comes into play, comprehends, as we have said, the sum of the purely psychical and purely intellectual phenomena of the living organism. It is the regio princeps of the organism, in which all ends, from which all begins, and which is the epitome of the vital forces of mental activity.

Now, how is this double sphere of activity, which from the dynamic point of view presents characters so distinctly marked, and yet so intimately fused together, constituted? How may it be ideally conceived as regards the cortical structure?