more developed; but we see clear enough that the nerves of nutrition have more to do than those of relation. This degree will be a ladder to get at the succeeding.

4th. Figure to yourself in the abdomen, a shade of stimulation higher than that which we stated just now it will be propagated to the heart, to the lungs, to the skin, to the members, to the different secretory vessels charged with the duty of depuration; it will extend even to the brain; for such is the human organization, that stimulation originating at one point of the body, cannot be propagated to a great number of organs, if it be not considerable enough to reach the brain. Here begins sensibility in the examples taken from men; for here perception first takes place from the painful sensations of different degrees, felt and referred to the stimulated viscera, or to the members, or to other regions of the nervous apparatus, whether internal or external. Perception having discovered sensibility, we ought, if we would understand the phenomena, study the different kinds of nerves that meet at the encephalon to produce it; and above all, the different states of the brain itself.

It is well known that, "to feel," can only be considered as a function of the brain; but if this organ be healthy and perfectly developed, it will give us feelings or sensations, that differ according to the nerves that have transmitted to it the stimulation. Placed between two classes of nerves, one of which terminates in sensitive expansions at the surface, and the other plunges among the visceral tissues, the brain receives two kinds of stimulations very different from each other. If we next examine each of these two classes of nerves, we shall find secondary differences well worthy of attention; and which prove that the brain has something else to do than to answer the stimulations of the senses vulgarly admitted by physiologists and metaphysicians. Each of our external senses is connected with a particular agent, which, being impressed, gives rise to a sensitive stimulation; and all of them are susceptible of another kind of stimulation, when some body, calculated to inflict a wound, penetrates into the nervous matter of the organ of sense. (The impression of light on the retina, produces a sensitive stimulation a body that lacerates the retina, produces a very different one.-Trans.)

The internal nerves also present notable differences. We find among them the genital senses, half external, half

All the internal senses, moreover, of a normal and regu lar character, have a distinction analagous to our external senses. In fact, the brain placed between these two classes of sense, the external and internal, is so organized, that in all the external perceptions that relate to the satisfaction of instinctive wants, and which first develope themselves, it cannot determine the action, but by means of other simultaneous or consecutive perceptions which proceed from the internal senses. We shall explain this very soon.

Let us state, as a fundamental fact in this question, that the brain, or rather the whole encephalic mass, is so organized as to reciprocate with these different sources of stimulation; that it acquires its full perfection slowly and with difficulty; that this degree of perfection corresponds with the like property of the various sources of stimulation; and that it perishes more or less readily as these do. The following observations will explain this.

Sec. 2d. Successive developement of the different functions of the nervous apparatus, from the embryo to the adult state.

In the first moment of his existence, man is no more than a diminutive mass of animal matter. He possesses no distinct organ. But the molecules of the mass arrange themselves according to the laws of an affinity which, we distinguish at a distance, so as to form successively the various animal tissues.

During all this effort of vital chemistry, (vital chrystalization.*-Trans.) the nerves and the encephalon have no occupation; they become developed, and that is all.

So soon as the tissues are formed, they act; each has its duty to perform; and the nervous commences upon its function, which is, to put stimulation in motion, and thus to determine the movements of all the other forms of animal matter. All subserving the regular transmission of nutritive matter to its destination, there to be subjected to the affinities of vital chemistry; for it can do nothing more important than press forward the developement of a human creature.

The nerves then, play the same part in the human embryo, that they perform in worms and other animals of a low class wherein we first observe them. In the embryo of a

*Chrystalization is the arrangement of molecules into some determinate form and shape, according to certain laws of attraction or affinity, equally unknown in the formation of rock chrystal or cubic pyrites, as in animal organization.--Trans.

has spoken, the infant recommences its cries. It is brought to the breast of the mother; immediately on contact it directs its face to her's, and all its motions to seize the breast and to work by suction and by swallowing are executed with precision.

This second want satisfied, the infant resumes his habitual calm, which the act of exoneration does not disturb, until the deposit of these matters on the linen, and irritation gradually produced by them on the skin, or some new demand on the stomach, or some extraordinary irritation again awakens him. Physiologists know that the alvine and urinary ejections do not take place but in concurrence with some action of the respiratory muscles. It is at least necessary that these muscles should follow the organs that return upon themselves for no vacuum could take place among viscera which touched each other. These respiratory muscles are under the control of the encephalon, which acts therefore in this case, in consequence of stimulations of the internal sense, belonging to the organs of evacuation, as well as of respiration; that is to say, without feeling pleasure or pain; but pain does accompany the internal gastric sense as well as too lively a stimulation of the skin. But if some obstacle should be felt either to respiration or defecation, the innervation of the bowels or of the urinary passages, or of the respiratory organs upon the brain, would increase and be felt with more or less vividness according as the encephalic development is more perfect.

These first perceptions are instinctive, as are the motions resulting from them. In the new born infant instinct reigns alone, but it is very limited. We shall see it increase as years increase. But as it may be confounded with intellect, we must seize the present occasion for distinguishing them. With the physiologist, it depends on the stimulations of the internal or external sensitive surfaces, propagated to the brain, and from thence reflected so as to produce muscular motion; which takes place either with pleasant or unpleasant perceptions, or without any perception which the observer can dis tinguish.

From this time then, we may distinguish two kinds of reaction in the brain, which receives stimulations from the nerves: 1st, reaction unaccompanied with pain or pleasure: 2ndly, reaction with one or other of these. All this, without any manifestation of intellect, and all possible to occur