difference is, that the latter are parts of a system, and the insect to which I have alluded constitutes a whole or entire self-moving structure. But the perfection with which the several organs of the body discharge their functions, when in a state of health, is as worthy of admiration as any phenomenon without us among the insect tribes. And we may presume, as they are none of them the works of man, that the evidence of wisdom should equally appear in one class of phenomena as in another-consequently, the perfection and efficiency of the acts as well as of the divine workmanship.

When a bone is broken, the surgeon does not in fact produce a union between the fractured ends. That process is effected by a power of self-restoration in the human body, to which his skill cannot reach ; and because he can go no farther, he calls it a law of the animal economy. He may, indeed, aid and assist, or he may thwart: so much power has been given to man, to good or to evil, over the body as well as the mind: but the ultimate efforts are not his own, nor can he wholly command their obedience.

Hence has arisen the term vis medicatrix naturæ, or healing power of nature, to designate a power implanted in the bodily constitution to preside over all its functions, vital and natural, for its support in health, and its preservation from injury,-a principle, powerfully active in effect, whether the term be admitted or rejected, and under all its appellations

meaning the same thing, though the cause be unknown. Therefore, whether it be called the purs of Hippocrates, the archæus of Van Helmont, the anima of Stahl, or the vis medicatrix of Cullen; whether it be dignified as the vital principle or degraded to mere mechanical and organic impulse; it is used to imply a mysterious innate faculty or power, from the moment of birth,-even from the first rudiments of living action,-ever watching and sustaining the body in its struggles with the various accidents of time to the last hour of human existence, when by an irreversible decree its efforts must cease.

CHAP. IV.

OF CERTAIN ACTIONS IN THE LOWER ANIMALS, IN SOME DEGREE DISTINGUISHABLE FROM THE OPERATIONS OF INSTINCT.

SECT. I.

On the effects of Human Intercourse on the lower Animals.

HAVING given a few examples of Instinct, or of a power operating above the conscious intelligence of the creature, I shall for the present digress from my immediate subject to notice certain actions of the lower animals; some of which seem to be referable to human instruction, some to a conscious intelligence or modified rationality in the creature, some to natural acuteness of the organs of sense, and some to the operation of a sense or faculty which appears to be altogether inexplicable.

It is pretty obvious that Instinct acts more immediately and determinately in the lower animals, like the appetites in man, for the preservation of the

individual and the multiplication of the species. The lower animals have also their appetites; but these are wisely placed under the government of Instinct, while the appetites of man require the controul of his higher principles.

The means which the brutes have of procuring food, of defending themselves from danger, and of providing for their offspring, are conducted with admirable skill and economy. This is an institution of nature under her own especial care. But beyond these objects we find them capable of many acts and services, which in various ways we turn to our own advantage.

We may perhaps adopt the general conclusion that Instinct governs the Brutes, and still admit the exception that some of their actions are not comprehended in this rule; as we may lay down the general position that man is a rational being, though we know that the conduct of many is often highly irrational; and, besides, many actions of the human frame are subject to the laws of instinct. But to draw the universal conclusion that man is under the exclusive dominion of Reason, and the brute under that of Instinct, would perhaps be assuming more than is consistent with sound philosophy.

It is, therefore, of importance to ascertain under what peculiar circumstances the lower animals exhibit phenomena of the doubtful character alluded to; so that some of the wisest men should say, the barrier between Instinct and Reason is too nice to be

apprehended; and, as Pope expresses it, "that these principles are for ever separate, yet for ever near.”

It appears, then, as far as we can range in the field of nature to survey the instincts of animals, that the farther they are removed from the confines of human intercourse, the more perfect are their instincts. And, on the contrary, the more their natural habits are changed by the artificial modes of life common in human Society, they lay aside pure instinct, and the more do the actions, at least of the more perfect animals, approach to the rule or line of rationality. Indeed, we see something of this kind to happen in our own species; for if instinct, as it is commonly understood, have any thing to do with the perfection of the senses, we know that in the rude or natural state of human society, they go far to excel those of the brute; and even the sight and hearing and smell are so wonderfully acute, as, in many important points relating to their personal advantages, to convey clearer information to the unenlightened Indian than the philosopher could attain by all his scientific experience. Hence, it would appear, that, as mankind is compressed in society, their instincts like those of the brute, give place to the culture of Reason: while, as man takes his range in the wilds of uncultivated nature, and seeks no other guide for his direction, his senses acquire a perfection which sometimes far exceeds the laboured deductions of reason. Dr. Gregory had a view somewhat similar to this, which he has expressed in the following passage: "Some