The use I shall make of these observations will appear very considerable in the application of them to the human form, which we are next to attempt.
It will be sufficient, therefore, at present only to observe, first, that the whole horn acquires a beauty by its being thus genteely bent two different ways; secondly, that whatever lines are drawn on its external surface become graceful, as they must all of them, from the twist that is given the horn, partake in some degree or other, of the shape of the serpentine-line: and, lastly, when the horn is split, and the inner, as well as the outward surface of its shell-like form is exposed, the eye is peculiarly entertained and relieved in the pursuit of these serpentine-lines, as in their twistings their concavities and convexities are alternately offer'd to its view. Hollow forms, therefore, composed of such lines are extremely beautiful and pleasing to the eye; in many cases more so, than those of solid bodies.
Almost all the muscles, and bones, of which the human form is composed, have more, or less of these kind of twists in them; and give in a less degree, the same kind of appearance to the parts which cover them, and are the immediate object of the eye: and for this reason it is that I have been so particular in describing these forms of the bent, and twisted, and ornamented horn.
There is scarce a straight bone in the whole body. Almost all of them are not only bent different ways, but have a kind of twist, which in some of them is very graceful; and the muscles annex'd to them, tho' they are of various shapes, appropriated to their particular uses, generally have their component fibres running in these serpentine-lines, surrounding and conforming themselves to the varied shape of the bones they belong to: more especially in the limbs. Anatomists are so satisfied of this, that they take a pleasure in distinguishing their several beauties. I shall only instance in the thigh-bone, and those about the hips.
The thigh-bone fig. [62 R p. II], has the waving and twisted turn of the horn, 58: but the beautiful bones adjoining, call'd the ossa innominata [Fig. 60 B p. II], have, with greater variety, the same turns and twists of that horn when it is cut; and its inner and outward surfaces are exposed to the eye.