Page:The Works of William Harvey (part 1 of 2).djvu/543

 one best adapted to effect the exclusion of the chick." It had been well after such a preface to have assigned satisfactory causes why hen's eggs are not spherical, like the eggs of fishes, worms and frogs, but oblong and pointed ; to have shown what there is in them which hinders the presumed perfection of figure. Now to me the form of the egg has never appeared to have aught to do with the engendennent of the chick, but to be a mere acci- dent; and to this conclusion I come the rather when I see such diversities in the shape of the eggs of different hens. They vary, in short, in conformity with the variety that obtains among the uteri of different fowls, in which, as in moulds, they receive their form.

Aristotle, 1 indeed, says that the longer-shaped eggs produce females, the rounder males. I have not made any experiments upon this point myself. But Pliny 2 asserts, in opposition to Aristotle, that the rounder eggs produce females, the others males. Now were there any certainty in such statements, either in one way or the other, some hens would always pro- duce males, others always females, inasmuch as the eggs of the same hen are in many instances always of one figure, namely, either much rounded or acutely pointed. Horace 3 thought that the oblong eggs, as being the more perfect and better con- cocted, and therefore the better flavoured, produced males.

I willingly pass by the reasons alleged by Fabricius for the form of eggs, as being all irrelevant.

The size of an egg appears to bear a proportion to the size of the foetus produced from it ; large hens, too, certainly lay large eggs. The crocodile, however, lays eggs the size of those of the goose ; nor does any animal attain to larger dimensions from a smaller beginning. It would seem, too, that the size of the egg and the quantity of matter it contained had some connexion with its fecundity, inasmuch as the very small eggs called centenines are all barren.

The number of eggs serves the same end as abundance of con- ceptions among viviparous animals they secure the perpetuity of the species. Nature appears to have been particularly care- ful in providing a numerous offspring to those animals which, by reason of their pusillanimity or bodily weakness, hardly

1 Hist. Auiin. lib. vi, cap. 2. * Lib. x, cap. 52. Plin. ibid.