THE WILL IN NATURE.
changes: but to this I shall soon return. Conjointly with this immutability of the anatomical element, we have the greatest susceptibility to modification, the greatest plasticity and flexibility of these same bones with reference to size, shape and adaptation to different purposes, all which we see determined by the will with primary strength and freedom according to the aims prescribed to it by external circumstances: it makes out of these materials whatever its necessity for the time being requires. If it desires to climb about in trees, it catches at the boughs at once with four hands, while it stretches the ulna [forearm bone opposite thumb side] and radius [forearm bone on thumb side] to an excessive length and immediately prolongs the os coccygis [bone at lower extremity of spine] to a curly tail, a yard long, in order to hang by it to the boughs and swing itself from one branch to another. If, on the other hand, it desires to crawl in the mud as a crocodile, to swim as a seal, or to burrow as a mole, these same arm-bones are shortened till they are no longer recognisable; in the last case the metacarpus [hand bone between wrist and fingers] and phalanges [fingers] are enlarged to disproportionately large shovel-paws, to the prejudice of the other bones. But if it wishes to fly through the air as a bat, not only are the os humeri, [upper arm bones] radius [forearm bone onthumb side] and ulna [forearm bone opposite thumb side] prolonged in an incredible manner, but the usually small and subordinate carpus [wrist], metacarpus [hand bone between wrist and fingers] and phalanges digitorum [finger bones] expand to an immense length, as in St. Anthony's vision, outmeasuring the length of the animal's body, in order to spread out the wing-membrane. If, in order to browse upon the tops of very tall African trees, it has, as a giraffe, placed itself upon extraordinarily high fore-legs, the same seven vertebra of the neck, which never vary as to number and which, in the mole, were contracted so as to be no longer recognisable, are now prolonged to such a degree, that here, as everywhere else, the neck acquires the same length as the fore-legs, in order to enable the head to reach down to drinking-water. But where, as is the case when it appears as the elephant, a long neck
COMPARATIVE
