CHAPTER I. MAN'S INTELLECTUAL NATURE BRIEFLY COMPARED WITH THAT OF THE ANIMALS NEXT BELOW HIM IN THE SCALE OF LIFE. MAN is distinguished from all other known animals, not only by his peculiar conformation of body-by his erect and dignified attitude-but by a far higher measure of intellectual endowment, and a consequently greater extension of his relations with external things. Remarkable, however, as this superiority of our species certainly is, still may it be questioned if, through human pride, it has not been something exaggerated, or a broader separation between us and the lower animals been assumed than Nature herself will acknowledge. Thus, by some metaphysical writers, all glimmerings of the higher mental faculties have been denied to brutes, and all their acts been ascribed to the direct impulse of a resistless instinct. This is evidently wrong; certainly in the physiological meaning of the word instinct. The simple animal instincts may be defined to be peculiar, inward feelings, or sensations originating urgent wants or desires, which stimulate or call forth certain muscular actions, whose purpose or end is, by satisfying the want, to re lieve the sensation that excited it; the series of physical actions produced being always understood to take place independent of education or imitation, and without any foresight. of the end to be attained by them. Or, to put the definition in another form: Instincts consist in particular physical conditions, and consequent sensations, impelling to some definite train of muscular movements, which contribute or are essential to the preservation of the individual, or the continuance of the species, and thus grow out of the "stimulus of necessity." Abundant examples illustrative of the foregoing definitions of instincts might be adduced, but the appetites of hunger and thirst will be sufficient for our purpose. These instinctive wants or desires are originated or excited by physical conditions of the stomach, or system at large, which demand the supply of food and drink, and thereby serve as monitors to solicit the co-operative acts requisite to furnish such supply. Hence animals, so soon as born, and independent, therefore, of either education or imitation, go through, and as perfectly as ever afterward, all those complicated muscular movements needful to meet the calls of nutrition. Instinctive feelings, when simple and uncontrolled, almost uniformly elicit instinctive actions. Simple, undiscerning, undeviating instinct-admitting such an unmixed principle-can obviously only exist in the humblest forms of animal life, as the invertebrata. In the lowest, even, of the vertebrata, or vertebral animals-those furnished with a spinal marrow and internal bony systemsome faint glimmerings of an intelligent principle begin to show themselves, mingling with, modifying and exercising some evident dominion over the mere instinctive operations. It is in this division of the animal kingdom that we begin to discover variations in individual character, in intelligence, in temper, &c.; and the higher we ascend in it, the greater is the degree of such variations. "Thus every one knows that there are stupid dogs and good-tempered dogs, as there are stupid men or good-tempered men. But no one could distinguish between a stupid bee and a clever bee, or between a good-tempered wasp and an ill-tempered wasp, simply because all their actions are prompted by an unvarying instinct."* Ascending in this division of animate being, we find the intelligent principle, with the faculty of reasoning, advancing, and apparently in correspondence with the development of the brain. And in man, whose brain is most fully developed-most complex in its fabric-the intellectual faculties are far more elevated than in any other example, as yet known, in animate nature. In him the instinctive propensities obviously become subject-though in different degrees in different individuals-to the nobler reasoning powers. Instinct will, I think, be generally found in the inverse ratio of reason—the latter faculty rendering it less necessary to animal preservation. It ever seems to be proportioned to the necessities for it. In the infant, instinct being the more necessary in the absence of reason, we observe more obvious traces of it than in the adult, though feeble compared with what the young of the inferior ani *Carpenter's Human Physiology. mals present. The human female shows undeniable evidences of a necessary instinct, in her strong love for her offspring on the instant of its birth, and sometimes even before its birth; in her impulsive desire to nourish it; her ceaseless care in its preservation, and her indomitable energy in its defence from danger. Unless her nature be perverted by disease, or entirely depraved by vice, the human can at first no more escape such instinctive feelings than the brute mother. But in the latter, they are transient-lasting only while their young need their protection; and, in some, they are evinced merely by the careful preparation for the welfare of their offspring before they come into existence; whereas, in the former, they soon becoming mingled with, modified, widened and strengthened, by feelings and principles far more exalted-of a moral and intellectual character-we have, growing out of such combination, the most devoted, the most enduring, the most self-sacrificing of all human affections—a mother's love. In the savage condition of man, especially as witnessed in the inferior races, the instinctive propensities are more marked, active, dominant, than in his state of civilization and intellectual advancement. In individual men, too, it will appear as a general truth, that the more eminently developed are the higher faculties of the mind, the less will be the instinctive manifestations. In living nature, all naturalists, I believe, admit, that there exists something like a gradually ascending chain, rising from the humblest plant, passing through the zoophyte, or transition link, to the animal scale, and so up ward to man-its highest limit as yet disclosed to human intelligence. In tracing, too, this rising chain of life, it will be seen that structure and function ever advance in a corresponding relation-the general development of the former being an unerring measure of the perfection of the latter. Thus, on reaching the naturalist's second great division of the animal kingdom, vertebrata, or that to which belong a brain and spinal marrow, we begin, as I previously remarked, to discover, in addition to the simple instinct which probably alone governs the lower or brainless animals, some faint evidences of powers of a higher mould, and which grow more and more clear, in proportion as the organization, particularly of the brain, approaches nearer and nearer to that of our own. Hence, in the class of animals whose brain and general nervous system most closely resemble man's, do we detect the rudiments of nearly all the human mental faculties, and consequently an approximation, imperfect, to be sure, still an obvious approximation to a rational nature. Although this gradation in the vegetable and animal kingdom-this gradual rise from the humblest to the loftiest organic forms-is sufficiently obvious in its general features, yet it cannot be denied that, in its particular parts, it will sometimes be found less direct and simple than might be inferred from the statements of many naturalists. Still, that there is a general, and mostly an easy advance in organic structure and function, will scarce be contradicted. A question here presents itself, How widely is man removed from the most manlike of the inferior animals? Do |