ife in general_ as an
abstraction, or as a mere heading under which all living beings are
inscribed. At a certain moment, in certain points of space, a visible
current has taken rise; this current of life, traversing the bodies it
has organized one after another, passing from generation to generation,
has become divided amongst species and distributed amongst individuals
without losing anything of its force, rather intensifying in proportion
to its advance. It is well known that, on the theory of the "continuity
of the germ-plasm," maintained by Weismann, the sexual elements of the
generating organism pass on their properties directly to the sexual
elements of the organism engendered. In this extreme form, the theory
has seemed debatable, for it is only in exceptional cases that there are
any signs of sexual glands at the time of segmentation of the fertilized
egg. But, though the cells that engender the sexual elements do not
generally appear at the beginning of the embryonic life, it is none the
less true that they are always formed out of those tissues of the embryo
which have not undergone any particular functional differentiation, and
whose cells are made of unmodified protoplasm.[8] In other words, the
genetic power of the fertilized ovum weakens, the more it is spread over
the growing mass of the tissues of the embryo; but, while it is being
thus diluted, it is concentrating anew something of itself on a certain
special point, to wit, the cells, from which the ova or spermatozoa will
develop. It might therefore be said that, though the germ-plasm is not
continuous, there is at least continuity of genetic energy, this energy
being expended only at certain instants, for just enough time to give
the requisite impulsion to the embryonic life, and being recouped as
soon as possible in new sexual elements, in which, again, it bides its
time. Regarded from this point of view, _life is like a current passing
from germ to germ through the medium of a developed organism_. It is as
if the organism itself were only an excrescence, a bud caused to sprout
by the former germ endeavoring to continue itself in a new germ. The
essential thing is the _continuous progress_ indefinitely pursued, an
invisible progress, on which each visible organism rides during the
short interval of time given it to live.

Now, the more we fix our attention on this continuity of life, the more
we see that organic evolution resembles the evolution of a