THE MEMORY IN EXERCISE.
those phenomena of memory into which the human personality more or less enters, there exist a whole series of similar acts which represent processes of memory to some extent incompletely developed.
These are those phenomena in which sensorial excitations, not having carried their action as far as the plexuses of conscious personality, remain in the condition of sterile materials, not perceived by the sensorium. Like those dark ultra-violet rays of the spectrum, which though not perceptible to our eyes, have nevertheless a real existence, they remain silently accumulated in the plexuses of the cerebral cortex, and only await the presence of an exciting cause capable of causing them to start from their obscurity.
Thus, we all know that during the period of our diurnal activity, there are a host of various impres sions which assail us on all sides, and even strike redoubled blows upon our sensitive plexuses, yet to which we pay no attention. The multifarious noises of carriages rolling around us all day, finally come to be unperceived by us and indifferent to us. We know also that when we give ourselves up to an absorbing intel lectual work, the ticking of the clock beside us strikes in vain upon our ears, and yet our acoustic nerves have been again and again set vibrating without our having a notion of it.
Onimus has made a very curious observation in con nection with this class of ideas. A man who was walking began automatically humming an air, being very much surprised by its having come into his head. It was only accidentally that he perceived that the air had been suggested to him by a wandering musician who was playing it on his instrument as he passed by, and whom he had not perceived.* This man in humming the air echoed an auditory impression, an unconscious reminiscence.
We all know that in examining a picture, or land scape, or a histological preparation, we first passively see the whole, and that certain details when we are not prepared for them at first escape us ; and if a per son, after we have gone to a distance from the object we have examined, retrospectively calls to our notice certain peculiarities of the object, we are quite astonished that we have remarked them, and that we recognize in ourselves the existence of certain impressions which have remained silent.
It is by means of unconscious impressions which persist in the brain that the activity of our spirit, in the automatic work which takes place in the act of reflection and meditation, is maintained.
It is thus that the unexplored sides of certain ques tions in suspense are made clear by the juxtaposition of old impressions which have arisen. A sort of auto
matic appeal is made to revived impressions which have some connection, and which come, as new factors, to enlighten our judgments with a number of new ideas.
The symptomatic study of mental maladies presents, as regards the subject, phenomena which are often very curious. We sometimes meet persons who have received an excellent education—ladies, young girls, living in the best society, above all taint of impurity, who, when seized with an attack of cerebral excitement, utter the grossest words, quite strange to their ordinary voca bulary.
Evidently, in these cases, the phenomena can only be explained thus :—That in walking in the streets or in public places, these gross phrases have unconsciously impressed them, and have remained in the state of latent memories buried in the cerebral tissue ; and that it is because of the morbid over-activity of the regions in which they are stored up that they are discovered and leap to light.
Local Memories.—It results from the anatomical arrangements, to which we have so many times directed attention, that the different groups of sensorial impres sions have each a special territory of distribution in the different regions of the sensorium, and that consequently there are in the human brain inequalities very clearly distinguished as regards the part devoted to each par ticular order of sensorial impressions. (Figs. 5 and 6.) It follows then from this inequality of development of similar regions in different individuals, that there exist special aptitudes for the reception of the different kinds of sensorial impressions. Thus it is that one person, whose optic cerebral regions are abundantly pro vided with well-endowed lively nerve-cells, will be fitted for clear perception of the external world—surrounding objects, with their colours and relations ; that another (Fig. 6.-14, 15), whose acoustic cerebral regions are largely developed will be predisposed to appreciate all the shades and delicacies of musical harmony ; while a third will have such and such an aptitude according to the preponderance of such and such a region of his brain ; and that thus, the special sensorial impressions, finding within such or such a circumscribed locality conditions of soil more favourable, agglomera tions of cells more dense and more lively—these impres sions will leave more enduring records, more vivid remembrances, and from this very fact richer stores of materials for fertilizing the psycho-intellectual activity in such or such a direction.