contact with the cuticle, but are surrounded with a semi-fluid matter. By this fluid and by the cuticle they are protected, at the same time that they are sensible to the pressure made on the surface, and to cutting, pricking, and heat.* But this capacity, we repeat, is not owing, strictly speaking, to any thing in the structure of the organ, but to the appropriation of the nerve to this class of sensations.

It is a curious confirmation of the fact, that the cutaneous nerve is adapted to receive impressions from the varieties of temperature, that when disease takes place in the centre of the trunk of a nerve, or when the nerve is surrounded with diseased parts, the sensation of burning accompanies the pain; and the patient refers this to the part of the skin to which the extreme branch of the nerve is distributed. By a burning sensation in the sole of the foot, I have been directed to the disease seated in the centre of the thigh.

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CHAPTER IX.

OF THE MUSCULAR SENSE.

Of the Sensibility of the Infant to Impressions, and the gradual improvement of the Sense of Touch.

A NOTION prevails that the young of animals are directed by instinct, but that there is an exception in regard to the human offspring: that in the child we have to trace the gradual dawn and progressive improvement of reason. This is not quite true; we doubt whether the body would ever be exercised under the influence of reason alone, and if it were not first directed by sensibilities which are innate or instinctive.

The sensibilities and the motions of the lips and tongue are perfect from the beginning; and the dread of falling is shewn in the young infant long before it can have had experience of violence of any kind.

The hand, which is to become the instrument for perfecting the other senses and developing the endowments of the mind itself, is in the infant absolutely powerless. Pain is poetically

described as that power into whose "iron grasp" we are consigned, to be introduced to a material world; now, although the infant is capable of an expression of pain, which cannot be misunderstood and is the same which accompanies all painful impressions during the whole life, yet it is unconscious of the part of the body which suffers. We have again recourse to the surgeon's experience. There occur certain congenital imperfections which require an operation at this early stage of life; but the infant makes no direct effort with its hand to repel the instrument, or to disturb the dressing, as it will at a period somewhat later.

The lips and tongue are first exercised; the next motion is to put the hand to the mouth, in order to suck it: and no sooner are the fingers capable of grasping, than whatever they hold is carried to the mouth. So that the sensibility to touch in the lips and tongue, and their motions, are the first inlets to knowledge; and the use of the hand is a later acquirement.

The knowledge of external bodies as distinguished from ourselves, cannot be acquired until the organs of touch in the hand have become familiar with our own limbs; we cannot be supposed capable of exploring any thing by the motion of the hand, or of judging of the form or tangible qualities of an object pressed against the skin, before we have a knowledge of our

own body as distinguished from things external

to us.

The first office of the hand, then, is to exercise the sensibility of the mouth: and the infant as certainly questions the reality of things by that test, as the dog does by its acute sense of smelling. In the infant, the sense of the lips and tongue is resigned only in favour of the sense of vision, when that sense has improved and offers a greater gratification, and a better means of judging of the qualities of bodies. The hand very slowly acquires the sense of touch, and many ineffectual efforts are seen in the arms and fingers of the child before the direction of objects or their distance is ascertained. Gradually the length of the arm, and the extent of its motions become the measure of distance, of form, of relation, and perhaps of time.

Next in importance to the sensibility of the mouth, we may contemplate that sense which is early exhibited in the infant, --the terror of falling. The nurse will tell us that the infant lies composed while she carries it in her arms up stairs; but that it is agitated in carrying it down. If an infant be laid upon the arms and dandled up and down, its body and limbs will be at rest, whilst it is raised; but they will struggle and make an effort as it descends. There is here the indication of a sense, an innate feeling of

danger, the influence of which we may perceive when the child first attempts to stand or run. When the child is set upon its feet, and the nurse's arms form a hoop around it without touching it, it slowly learns to balance itself and stand; but under a considerable apprehension. Presently, it will stand at such a distance from the nurse's knee, that if it should lose its balance, it can throw itself for protection into her lap. In these its first attempts to use its muscular frame, it is directed by an apprehension which cannot as yet be attributed to experience. By degrees it acquires the knowledge of the measure of its arm, the relative distance to which it can reach, and the power of its muscles. Children, therefore, are cowardly by instinct: they show an apprehension of falling; and we may gradually trace the efforts which they make, under the guidance of this sensibility, to perfect the muscular sense. In the mean time, we perceive how instinct and reason are combined in early infancy how necessary the first is to existence: how it is subservient to reason: and how it yields to the progress of reason, until it becomes so obscured that we can hardly discern its influence.

When treating of the senses, and showing how one organ profits by the exercise of the other, and how each is indebted to that of touch, I was led to observe that the sensibility of the skin is the most dependant of all on the exercise of