The limbs that take their shape from the muscles of locomotion, and the internal parts concerned in those high vital offices, of which minerals and vegetables are wholly destitute, are examples and proof of the configuration proper to the animal kingdom. The thigh, leg, arm, fore-arm, finger, the neck and shoulders, the chest, and the abdomen meeting it and resting on the pelvic bones, are felt to be beautiful or true to the standard form as they taper or conform to this intuitive life-type.
The glands are all larger at one end than the other, and those that have the highest uses are most conspicuously so, and have the best defined and most elegant contour. The descending grade of figure and function is marked by tendency to roundness and flatness. In the uses, actions and positions of these organs, there is nothing mechanical to determine their figure. The human stomach is remarkable for an elegance of form and conformity to the ideal or pattern configuration, to a degree that seems to have no other cause, and, therefore, well supports the doctrine that the importance of its office confers such excellence of shape. The facts of comparative anatomy cannot be introduced with convenience, but they are believed to be in the happiest agreement and strongest corroboration.
The heart, lungs and brain, are eminent instances of the principle. They hold a very high rank in the organization, and, while their automatic relations, uses and actions are toto cœlo dissimilar, their agreement with each other in general style of configuration, and their common tendency toward the standard intimated, is most remarkable.
Their near equality of rank and use, as measured by the significance of form, over-rides all mechanical difference in their mode of working. The heart is, in office, a forcing pump or engine of the circulation. The lungs have no motion of their own, and the porosity or cellular formation of the sponge seems to be the only quality of texture that they require for their duty, which is classed as a process of vital chemistry. The brain differs, again, into a distinct category of function, which accepts no classification, but bears some resemblance to electrical action. Yet, differing thus by all the unlikeness that there is between mechanical, chemical and electro-vital modes of action, they evidently derive their very considerable resemblance of figure from their nearly equal elevation and dignity of service in the frame. This near neighborhood of use and rank allows, however, room enough for their individual differences and its marks. The heart is lowest of the three in rank, and nearest the regularly conical form. The lungs, as their shape is indicated by the cavity which they occupy, are more delicately tapered at their apex, and more oblique and variously incurvated at their base. And the brain, whether viewed in four compartments, or two, or entire, (it admits naturally of such division,) answers still nearer to the highest style and form of the life pattern; and with the due degree of resemblance, or allusion to it, in its several parts, according to their probable value; for the hemispheres are shaped much more conformably to the ideal than the cerebellum or the cerebral apparatus at the base of the brain, where the office begins to change from that of generating the nervous power to the lower service of merely conducting it out to the dependencies.
IV. Hitherto we have looked for proof and illustration only to well marked and clearly defined examples of the orders and kinds of things examined. But the borders of kingdoms and classes, the individuals which make the transitions, and the elements and qualities common to several provinces which link kind to kind and rank to rank, confess the same law, and even more nicely illustrate where, to superficial view, they seem to contradict it.
Every species of beings in the creation is a reproduction, with modifications and additions, but a real reproduction, in effect, of all that is below it in the scale; so that the simplest and the lowest continues and reappears in all, through all variety of advancement, up to the most complex and the highest; in some sense, as decimals include the constituent units, and hundreds include the tens, and other multiples of these embrace them again, until the perfect number is reached, if there be any such bound to either numerals or natures.
1. The rectilinear and parallel arrangement of parts proper to crystalization, which is the lowest plastic power of nature known to us, continues, proximately, in the stems and branches of vegetables. This will accord with our theory, if ascribed to the abundant mineral elements present in the woody fibre, and to its insensibility and enduring nature, as shown by its integral preservation for ages after death, to a degree that rivals the rocks themselves. But the stems of trees are not exactly cylindrical and their fibres are not quite parallel; for there is something of life in them that refuses the arrangement of dead matter. From root to top they taper, but so gradually that it is only decidedly seen at considerable distances or in the whole length.
2. A section of a timber tree shows a regular concentric arrangement of rings—the successive deposits of sequent years—and its cleavage proves that it has also a radiated disposition of fibres. In the flat bones of the head this same arrangement of parts obtains. The cartilaginous base of bone has a life of perhaps equal rank with that of the vegetable structure; it has its insensibility, elasticity, and durability at least, with scarcely any higher qualities; and the osseous deposit is thrown into figure and order similar to the ligneous.
3. The fruits, kernels, and seeds of plants, being the highest results of the vegetable grade of living action, and so bordering upon the sphere of animal existence, and even intruding into it, begin to take its proper forms, and they are spheroidal, oblate spheroids, conical exactly, ovoid, and even closely touch upon the heart-shaped; yet without danger of confusion with the forms distinctive of the higher style of life. This comparison, it must be remarked also, is between the fruits of one kind and the organic structures of the other, and not of organ with organ, which in different kinds shows the greatest diversity, but of spheres of existence immediately contiguous, and therefore closely resembling each other.
V. Of these forms the globular is probably the very lowest; and, accordingly, of it we have no perfect instance in the animal body, and no near approach to it, except the eye-ball, where mechanical law compels a rotundity, that muscle, fat, and skin seem employed to hide as well as move and guard, and, in the round heads of bones, where the ball and socket-joint is required for rotatory motion. But in both these cases the offices which the roundness serves are mechanical, and so, not exceptions to our rule. The perfectly spherical must rank as a low order of form, because it results from the simplest kind of force, mere physical attraction being adequate to its production, without any inherent modifying power or tendency in the subject. It is, accordingly, very repugnant to taste in the human structure; as, for instance, rotundity of body, or a bullet-head. Nothing of that regularity of curve which returns into itself, and might be produced upon a turning lathe, and no continuity of straight lines within the capacity of square and jack-plane, are tolerable in a human feature. Lips, slit with the straightness of a button-hole, or conical precision, or roly-poly globularity, would be equally offensive in the configuration of any feature of the face or general form. Cheek, chin, nose, brow, or bosom, put up into such rotundity and uniformity of line and surface, have that mean and insignificant ugliness that nothing can relieve. In raggedest irregularity there is place and space for the light and shade of thought and feeling, but there is no trace or hint of this nobler life in the booby cushiony style of face and figure. Nose and brows, with almost any breadth of angle; and chin, with any variety of line and surface, are better, just as crystalization, flat and straight and sharp as it is, nevertheless, seems to have some share in its own make and meaning, which rolls and balls cannot lay any claim to.