Their parts are perfectly framed for generation, and they have a wonderful propensity to copulation.

When the seed has fallen on the matrix, it draws almost all the nourishment to itself, by which the foetus is formed; but as soon as it is discharged from thence, if it is an animal that is nourished by milk, almost all the food of the mother turns into milk, and the animal, without any direction but by the pure instinct of nature, immediately hunts for the teat, and is there fed with plenty.

What makes it evidently appear that there is nothing in this fortuitous, but the work of a wise and foreseeing nature, is, that those females which bring forth many young, as sows and bitches, have many teats, and those which bear a small number have but few.

What tenderness do beasts show in preserving and raising up their young till they are able to defend themselves! They say, indeed, that fish, when they have spawned, leave their eggs; but the water easily supports them, and produces the young fry in abundance.
LII.

It is said, likewise, that tortoises and crocodiles, when they have laid their eggs on the land, only cover them with earth, and then leave them, so that their young are hatched and brought up without assistance; but fowls and other birds seek for quiet places to lay in, where they build their nests in the softest manner, for the surest preservation of their eggs; which, when they have hatched, they defend from the cold by the warmth of their wings, or screen them from the sultry heat of the sun.