DEVELOPMENT OF SENSIBILITY.
in living beings awakens with life. As regards histological sensibility proper, it is inherent in the primordial phenomena of the evolution of the embry onic cells ; it is a hereditary legacy which accumulates incessantly, by the addition of new elements, and new tissues, in proportion as the organism completes and perfects itself.
It is by virtue of the individual sensibility of the em bryonic cells that these borrow from the surrounding medium, the fluid atmosphere which bathes them, the elements suitable for their special nutrition, and that the nervous system itself appears as an apparatus of centralization and organic perfectionment.
In the first phases of foetal life it is very difficult to fix definitely at what epoch sensibility manifests itself as a motor force ; nevertheless, from the fourth month we can observe that the nervous system begins to react and to reveal the vitality of the different apparatuses of which it is made up.
We know, indeed, that from this period the fcetas is sensitive to the action of cold, and that we can develop its spontaneous movements by applying a cold hand to the abdomen of the mother. We know also that it executes spontaneous movements to withdraw from pressure that constrains it and brings its sensibility into play.
\Ve may then legitimately conclude that here we have the first gleams of awakening sensibility, which from this period is transmitted through its natural channels by the nervous system, and already regulated in the manner in which it will subsequently manifest itself throughout the organism.
At birth it is the entire cutaneous sensibility, suddenly awakened by the irruption of the young being into a cold atmosphere, which determines its first startled cries, and its first inspirations. It is, then, in the sensitive peripheral regions that the first sparks which are to develop the play of the organic machinery, and those excitations of the vital knot which once set in motion will only cease at the end of life, have their origin.
From this time forth the child takes the breast of the nurse automatically, and by virtue of hereditary vital forces which already exist in a latent state in his nervous system. His organic appetites are gratified by the milk he sucks, and he feeds himself organically, like an organic cell, which borrows from the surrounding medium the materials which suit it. But at the same time he ex presses the satisfaction he feels in his own manner ; he smiles on seeing the breast which yields him his nourish ment and life, and from that time his natural sensibility is thrown into agitation, his sensorium is affected. He rejoices because he remembers, because he has retained a memory of the satisfaction of his physical appetites.
Here, in these first phases of the manifestations of human sensibility, is the rudimentary formula according to which the moral sensibility of the human being shall henceforth be evolved in the course of his life, and already such as we have found it in the adult—that is to say, reducible to a purely sensitive phenomenon multiplied by the intervention of memory and intelligence.
From these first moments onwards sensibility develops rapidly.
The different sensorial foci by the aid of which it comes to life, light up, multiply, and successively attain to perfection. The child successively learns to see, hear, feel, smell, and taste. He remembers satisfactions re ceived. He recognizes the persons who immediately surround him and load him with caresses. It was the sight of the bosom of his nurse which in the first instance excited his first smiles, and as his field of vision extends, it is the entire person of his nurse to which these Arne smiles appeal ; then, as it extends still further, he re cognizes those whom he frequently sees, and who present a pleasant physiognomy to him.
Soon, by the progressive unfolding of all the latent activities of the organic elements which come into exist ence, the general life of the child develops in ample luxuriance.