for a quite specially determined way of life, for the element in which the prey dwells, for the pursuit, the overcoming, the crushing and digesting of that prey,--all this, we say, proves, that the animal's structure has been determined by the mode of life by which the animal desired to find its sustenance, and not _vice versa_. It also proves, that the result is exactly the same as if a knowledge of that mode of life and of its outward conditions had preceded the structure, and as if therefore each animal had chosen its equipment before it assumed a body; just as a sportsman before starting chooses his whole equipment, gun, powder, shot, pouch, hunting-knife and dress, according to the game he intends chasing. The latter does not take aim at the wild boar because he happens to have a rifle: he took the rifle with him and not a fowling-piece, because he intended to hunt the wild boar; and the ox does not butt because it happens to have horns: it has horns because it intends to butt. Now, to render this proof complete, we have the additional circumstance, that in many animals, during the time they are growing, the effort of the will to which a limb is destined to minister, manifests itself before the existence of the limb itself, its employment thus anticipating its existence. Young he-goats, rams, calves, for instance, butt with their bare polls before they have any horns; the young boar tries to gore on either side, before its tusks are fully developed which would respond to the intended effect, while on the other hand, it neglects to use the smaller teeth it already has in its mouth and with which it might really bite. Thus its mode of defending itself does not adapt itself to the existing weapons, but _vice versa_. This had already been noticed by Galenus[226] and by Lucretius[227] before him. All these circumstances give us complete certainty, that the will does not, as a supplementary thing proceeding from the intellect, employ those instruments which it may happen to find, or use the parts because just they and no others chance to be there; but that what is primary and original, is the endeavour to live in this particular way, to contend in this manner, an endeavour which manifests itself not only in the employment, but even in the existence of the weapon: so much so indeed, that the use of the weapon frequently precedes its existence, thus denoting that it is the weapon which arises out of the existence of the endeavour, not, conversely, the desire to use it out of the existence of the weapon. Aristotle expressed this long ago, when he said, with reference to insects armed with stings:[228] διὰ τὸ θυμὸν ἔχειν ὅπλον ἔχει (_quia iram habent, arma habent_), and further on, generally speaking:[229] Τὰ δ' ὄργανα πρὸς τὸ ἔργον ἡ φύσις ποιεῖ, ἀλλ' οὐ τὸ ἔργον πρὸς τὰ ὄργανα (_Natura enim instrumenta ad officium, non officium ad instrumenta accommodat_). From which it follows, that the structure of each animal is adapted to its will.