such as ought to be interrupted? The next day all past
fatigue is gone and vanished. The animal works on, as if he had
never worked before; and this reviving gives him a vivacity and
vigour that invites him to new labour. Thus the nerves are still
full of spirits, the flesh smooth, the skin whole, though one would
think it should waste and tear; the living body of the animal soon
wears out inanimate bodies, even the most solid that are about it;
and yet does not wear out itself. The skin of a horse, for
instance, wears out several saddles; and the flesh of a child,
though very delicate and tender, wears out many clothes, whilst it
daily grows stronger. If this renewing of spirits were perfect, it
would be real immortality, and the gift of eternal youth. But the
same being imperfect, the animal insensibly loses his strength,
decays and grows old, because everything that is created ought to
bear a mark of nothingness from which it was drawn; and have an end.

SECT. XXVI. Of Generation.

What is more admirable than the multiplication of animals? Look
upon the individuals: no animal is immortal. Everything grows old,
everything passes away, everything disappears, everything, in short,
is annihilated. Look upon the species: everything subsists,
everything is permanent and immutable, though in a constant
vicissitude. Ever since there have been on earth men that have
taken care to preserve the memory of events, no lions, tigers, wild
boars, or bears, were ever known to form themselves by chance in
caves or forests. Neither do we see any fortuitous productions of
dogs or cats. Bulls and sheep are never born of themselves, either
in stables, folds, or on pasture grounds. Every one of those
animals owes his birth to a certain male and female of his species.

All those different species are preserved much the same in all ages.
We do not find that for three thousand years past any one has
perished or ceased; neither do we find that any one multiplies to
such an excess as to be a nuisance or inconveniency to the rest. If
the species of lions, bears, and tigers multiplied to a certain
excessive degree, they would not only destroy the species of stags,
bucks, sheep, goats, and bulls, but even get the mastery over
mankind, and unpeople the earth. Now who maintains so just a
measure as never either to extinguish those different species, or
never to suffer them to multiply too fast?

But this continual propaga