Page:The Works of William Harvey (part 1 of 2).djvu/449

 nor as an animate substance transferring its vitality (anima) to the chick. For in the egg there is no semen, neither does any touch it, nor has ever done so ; (" and it is impossible that that which does not touch should move, or that anything should be affected by that which does not move it,") and there- fore the vitality of the semen ought not to be said to exist in it ; and although the vital principle may be the efficient in the egg, yet it would not appear to result more from the cock or his semen, than from the hen.

Nor, indeed, is it transferred by any metempsychosis or translation from the cock and his semen into the egg, and thence into the chick. For how can this translation be carried on into the eggs that are yet to exist, and to be conceived after intercourse ? unless either some animate semen be in the mean time working in some part of the hen ; or the vital principle only have been translated without the seed, in order to be infused into any egg which might thereafter be produced ; but neither of these alternatives is true. For in no^part of the hen is the semen to be found ; nor is it possible that the hen after coition should be possessed of a double vital principle, to wit, her own, and that of the future eggs and chicks; since " the living principle or soul is said to be nowhere but in that thing whose soul it is," much less can one or more vital prin- ciples lie hidden in the hen, to be afterwards subservient to the future eggs and chicks in their order, as they are produced.

We have adduced these passages out of Aristotle in order to set forth his opinion of the manner in which the seed of the cock produces the chick from the egg ; and thereby throw at least some light on this difficult question. But whereas the said passages do not explain the mode in which this is ac- complished, nor even solve the doubts proposed by himself, it appiears that we are still sticking in the same mud, and caught in the same perplexities (concerning the efficient cause of the foetus in the generation of animals ;) indeed, so far from Aris- totle's arguments rendering this question more clear, they ap- pear on the contrary to involve it in more and greater doubts.

Wherefore it is no wonder that the most excellent philoso- pher was in perplexity on this head, and that he has admitted so great a variety of efficient causes, and at one time has been compelled to resort to automatons, coagulation, art, instruments,