the act of generation, the testes and vasa deferentia in the male, the ovarium and uterus and blood-vessels supplying them in the female are all contrived with such signal art and forethought, and everything requisite to reproduction in a determinate direc- tion situation, form, temperature, arranged so admirably, it seems certain, as nature does nothing in vain, nor works in any round-about way when a shorter path lies open to her, that an egg can be produced in no other manner than that in which we now see it engendered, viz., by the concurring act of the cock and hen. Neither, in like manner, in the present constitution of things, can a cock or hen ever be produced otherwise than from an egg. Thus the cock and the hen exist for the sake of the egg, and the egg, in the same way, is their antecedent cause ; it were therefore reasonable to ask, with Plutarch, which of these was the prior, the egg or the fowl ? Now the fowl is prior by nature, but the egg is prior in time ; for that which is the more excellent is naturally first ; but that from which a certain thing is produced must be reputed first in respect of time. Or we may say : this egg is older than that fowl (the fowl having been produced from it) ; and, on the contrary, this fowl existed before that egg (which she has laid). And this is the round that makes the race of the common fowl eternal ; now pullet, now egg, the series is continued in perpetuity ; from frail and perishing individuals an immortal species is engendered. By these, and means like to these, do we see many inferior or ter- restrial things brought to emulate the perpetuity of superior or celestial things.
And whether we say, or do not say, that the vital principle (anima) inheres in the egg, it still plainly appears, from the circuit indicated, that there must be some principle influencing this revolution from the fowl to the egg and from the egg back to the fowl, which gives them perpetuity. Now this, according to Aristotle's views, 1 is analogous to the element of the stars ; and is that which makes parents engender, and gives fertility to their ova; and the same principle, Proteus like, is present under a different form, in the parents as in the eggs. For, as the same intelligence or spirit which incessantly actuates the mighty mass of the universe, and compels the same sun from
1 De Gener. Anim. lib. ii, cap. 3.
