be subsequently determined, and whatever is necessary to the constitution of a perfect animal arranged. For if this principle were at any time extrinsic, and entered into the body at a sub- sequent period, you would not only be in doubt as to the time at which it entered, but as every part is distinct, you would also see it as necessary that that should first exist from which the other parts derive both increase and motion." The same writer elsewhere l asserts : " This principle is a portion of the whole, and not anything added, or included apart. For," he proceeds, "the generation of the animal completed, does this principle perish, or does it continue ? But nothing can be shown existing intrinsically which is not a part of the whole organized being, whether it be plant or animal; wherefore it would be absurd to maintain that the principle in question perished after the formation either of any one or of any number of parts; for what should form those that were not yet produced? Wherefore," he continues further, " they say not well who with Democritus assert that the external parts of animals are those first seen, and then the internal parts, as if they were rearing an animal of wood and stone, for such a thing would include no principle within itself. But all animals have and hold a principle in their interior. Wherefore the heart is seen as the first distinct part in animals that have blood ; for it is the origin of all the parts, whether similar or dissimilar ; and the creature that begins to feel the necessity of nourishment, must already be possessed by the principle of an animal and a full-grown foetus."
From the above, it clearly appears that Aristotle recognizes a certain order and commencement in animal generation, namely, the heart, which he regards as the first produced and first vivified part of the animal, and, like a son set free from the tutelage of his parents, as self-sufficing and independent, whence not only does the order of the parts proceed, but as that by which the animal itself is maintained and preserved, receiving from it at once life and sustenance, and everything needful to the perfection of its being. For as Seneca says : 2 "In the semen is comprised the entire cause of the future man; and the unborn babe has written within it the law of a beard and a
1 De Gen. Anim. lib. ii, cap. 1. * Nat. Quaest. lib. iii, cap. 29.
