ncies is always implied? In particular, it may be said
of individuality that, while the tendency to individuate is everywhere
present in the organized world, it is everywhere opposed by the tendency
towards reproduction. For the individuality to be perfect, it would be
necessary that no detached part of the organism could live separately.
But then reproduction would be impossible. For what is reproduction, but
the building up of a new organism with a detached fragment of the old?
Individuality therefore harbors its enemy at home. Its very need of
perpetuating itself in time condemns it never to be complete in space.
The biologist must take due account of both tendencies in every
instance, and it is therefore useless to ask him for a definition of
individuality that shall fit all cases and work automatically.

But too often one reasons about the things of life in the same way as
about the conditions of crude matter. Nowhere is the confusion so
evident as in discussions about individuality. We are shown the stumps
of a Lumbriculus, each regenerating its head and living thence-forward
as an independent individual; a hydra whose pieces become so many fresh
hydras; a sea-urchin's egg whose fragments develop complete embryos:
where then, we are asked, was the individuality of the egg, the hydra,
the worm?--But, because there are several individuals now, it does not
follow that there was not a single individual just before. No doubt,
when I have seen several drawers fall from a chest, I have no longer the
right to say that the article was all of one piece. But the fact is that
there can be nothing more in the present of the chest of drawers than
there was in its past, and if it is made up of several different pieces
now, it was so from the date of its manufacture. Generally speaking,
unorganized bodies, which are what we have need of in order that we may
act, and on which we have modelled our fashion of thinking, are
regulated by this simple law: _the present contains nothing more than
the past, and what is found in the effect was already in the cause_. But
suppose that the distinctive feature of the organized body is that it
grows and changes without ceasing, as indeed the most superficial
observation testifies, there would be nothing astonishing in the fact
that it was _one_ in the first instance, and afterwards _many_. The
reproduction of unicellular organisms consists in just this--the living
being divides into two halves,