CHAPTER II.

THE PHYSICAL CHARACTER OF MAN.

SECTION I.

The Physical Character of Man, compared with that of other Animals.

ALTHOUGH, when viewed in the aggregate of his faculties, moral as well as physical, man confessedly holds the first rank among animals; yet, if we exclude from our consideration those intellectual powers and moral qualities by which he is essentially characterized, and confine our view to his mere animal nature, we find that he scarcely differs in any important point from any of the species of the higher classes. In each there is the same necessity for air, and sleep, and food; and the nature of the food and the mode of its digestion are not materially different, the nutrient fluid extracted by the process of digestion is converted into blood of the same character and distributed in the same manner through the system: the constituent parts of the body and their mode of growth are almost precisely the same; for the bone, muscle, tendon, skin, hair, and brain of the horse, or deer, or tiger, or bear, scarcely differ in their physical or chemical characters from the corresponding parts in man: similar secretions, as the bile, tears, and saliva, are separated by similarly constructed organs; and similar parts become similarly diseased: the special senses of sight, hearing, taste, and smell, are exercised through the medium of similar organs, simply modified according to the particular wants of individual species: the sources of mere bodily pain or pleasure are generally the same: the instinctive affections, passions, and propensities

are the same, and are manifested in the same way; the angry look of a dog, for instance, bespeaking the internal feeling as strongly as that of a man; and the playful and rapid movements of the young puppy resembling the careless hilarity of childhood, no less than the stayed motions and wary eye of the aged hound resemble the sedateness of the aged human being.

Probably, however, it would be nearer the truth, were we to say that man, if divested of his intellectual powers, and endued merely with his animal nature, would be inferior to the brutes; for, possessing, as is the case, very few of the prospective or preservative instincts, he would be unable, without the aid of his intellectual powers, to provide for some of his most imperious wants.

But we may go even further than this. Let us suppose, for instance, a community of human individuals, who, though not gifted with a sufficient degree of intellectual powers to instruct others, or improve themselves, were yet endued with them to a degree sufficient to render them, if the opportunity offered, docile to a certain extent, and capable of executing many of the common offices of life; (and what town or village does not present to our observation individual instances of such unhappy shadows of human nature?) how could a community like this exist; in which, though all, by the terms of the suposition, were capable of learning something, yet none would be capable of teaching any thing? of what use under these circumstances would be that "instrument of instruments" the human hand, where there was no presiding mind to direct its movements? And, with respect to that wonderful auxiliary of the human powers, how incorrect is the reflection of those who have asserted that men are superior to brutes, only because they possess this instrument: and how truly philosophical is the opposite reflection, that man is not superior to other animals because he possesses this instrument; but he is provided with such an in

strument precisely because he is already "superior to all other animals. And the converse is equally true, that, with intellectual powers of even a higher order than those which they already possess, human beings could not live in a state of society, could hardly indeed exist in any state, unless furnished with such an instrument as the hand.

SECTION II.

Differences in the Form of the Infant and of the Adult; particularly with reference to the Spine.

AND yet, notwithstanding the confessed superiority of man, if we view him only in the infancy of his in-, dividual existence, what is there that is calculated to give an earnest of his future vigour and activity, either with respect to bodily or mental powers; and what are all the advantages of the external world to a creatrue so utterly helpless, so utterly incapable of using or even passively enjoying them? In fact, with the exception of a very few instinctive rather than voluntary acts, such as that of deriving its nutriment from the mother's breast, the infant is, from the feebleness of its powers, incapable of efficient exertion; and depends entirely on the assistance of those around it.

The physical differences, observable in comparing the structure of the infant with that of the adult, which enable the one to execute many operations of which the other is incapable, exist to a certain extent in every part of the body; but are perhaps more remarkable in the spine than in any other part and the spine therefore may be selected as a fit term of comparison.

In considering the office of the adult spine, with a view to the present subject, we find that great strength combined with great flexibility, is particularly requisite. with reference to strength, the py ramidal form of this natural column is obviously

conducive to the purpose intended: and the arrangement of the solid matter, of which it is composed, is such as to contribute to the same effect; for that solid matter, instead of being collected into one compact mass, is diffused in such a manner as to resemble the structure of sponge; and it is well known, with reference to the strength of artificial columns, that, the same quantity of matter being given for each, and their height being the same, those columns which are hollow are stronger than those which are solid.Again, the whole column is made up of numerous parts, called vertebræ, which are so firmly bound together as to lessen the chance of being broken in the act of bending; and these vertebræ being applied to each other, throughout, by broad horizontal surfaces, are thus best calculated to support the perpendicular pressure of the superincumbent parts.

The effect of general strength is further accomplished by the mutual locking in of the projecting portions, or processes, of the several vertebræ; and the same effect is accomplished to an additional extent among these vertebræ which belong to the thorax or chest, by the mode of articulation between them and the ribs; each rib being united, not entirely to a single vertebra, but partially to two contiguous vertebræ, near their line of junction.

The flexibility of the spine is secured to the utmost requisite extent, by the great number of articulations or joints which it possesses, amounting to more than twenty; as well as by the elasticity of the substance constituting those joints: and the projecting parts or processes of the several vertebra, which serve for the insertion of the muscles and tendons which are to move the whole, are differently disposed in the neck, the back, and the loins; so as to be accommodated to the degree and kind of motion required in each: thus the vertebræ of the neck admit of a lateral motion to a greater extent than those of the back, and the vertebræ of the back admit of flexion and extension to a greater degree than those of the neck;

while the vertebræ of the loins, being intended for support rather than flexibility, have their processes so distributed, as to contribute principally to the former of those effects.

Thus far we have considered the conditions of the adult spine, and have seen that they are calculated most admirably both for flexibility and for strength. Let us now examine the same column in the age of early infancy; and here we shall see, that, although at that period the parts, in which the conditions of strength and flexibility are so remarkably developed in the adult state, are not yet formed, or not completed; those parts which are essential to the security of the life of the individual are nearly in as perfect a state as at the age of manhood; so that in the midst of the most decided marks of weakness and imperfection in the rest of the column, there is an extraordinary instance of strength and perfect growth, in precisely that part of it which could not have been left in an incomplete state, without manifest, immediate and constant danger to the individual. In other words, the bodies and processes of the several vertebræ on which the strength and flexibility of the spine depend, are in early infancy still in a soft or cartilaginous state; while the annular portions, which with their intervening ligaments constitute the spinal canal, are completely ossified; so as to give as great a degree of security to the spinal marrow as at the age of manhood.

Nor need we spend much time in ascertaining the final cause of this remarkable difference. Is it not indeed obvious on a moment's reflection, that the very helplessness and imperfect state of the physical powers in infancy, so ill understood and appreciated, though so beautifully described by Lucretius, contribute to the fuller development ofthe moral character, not only of the individual, but of his parents also, and of all his immediate connexions. The mutual affection, for instance, that takes place and is cemented between the infant and its mother, during