possessed by these animals are controlled by the same governing tendency.
Cut off the legs, the tail, the jaws, separately or all together, and, as
Spallanzani showed long ago, these parts not only grow again, but the
redintegrated limb is formed on the same type as those which were lost. The
new jaw, or leg, is a newt's, and never by any accident more like that of a
frog. What is true of the newt is true of every animal and of every plant;
the acorn tends to build itself up again into a woodland giant such as that
from whose twig it fell; the spore of the humblest lichen reproduces the
green or brown incrustation which gave it birth; and at the other end of
the scale of life, the child that resembled neither the paternal nor the
maternal side of the house would be regarded as a kind of monster.

So that the one end to which, in all living beings, the formative impulse
is tending--the one scheme which the Archaeus of the old speculators strives
to carry out, seems to be to mould the offspring into the likeness of the
parent. It is the first great law of reproduction, that the offspring tends
to resemble its parent or parents, more closely than anything else.

Science will some day show us how this law is a necessary consequence of
the more general laws which govern matter; but, for the present, more can
hardly be said than that it appears to be in harmony with them. We know
that the phaenomena of vitality are not something apart from other physical
phaenomena, but one with them; and matter and force are the two names of the
one artist who fashions the living as well as the lifeless. Hence living
bodies should obey the same great laws as other matter--nor, throughout
Nature, is there a law of wider application than this, that a body impelled
by two forces takes the direction of their resultant. But living bodies may
be regarded as nothing but extremely complex bundles of forces held in a
mass of matter, as the complex forces of a magnet are held in the steel by
its coercive force; and, since the differences of sex are comparatively