The Origin of Species | Page 6

as if a delicate finger
traced out the line to be occupied by the spinal column, and moulded
the contour of the body; pinching up the head at one end, the tail at the
other, and fashioning flank and limb into due salamandrine proportions,
in so artistic a way, that, after watching the process hour by hour, one is
almost involuntarily possessed by the notion, that some more subtle aid
to vision than an achromatic, would show the hidden artist, with his
plan before him, striving with skilful manipulation to perfect his work.
As life advances, and the young amphibian ranges the waters, the terror
of his insect contemporaries, not only are the nutritious particles
supplied by its prey, by the addition of which to its frame, growth takes
place, laid down, each in its proper spot, and in such due proportion to
the rest, as to reproduce the form, the colour, and the size, characteristic
of the parental stock; but even the wonderful powers of reproducing
lost parts 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 phenomena of vitality are not something
apart from other physical phenomena, 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
slight, or, in other words, the sum of the forces in each has a very
similar tendency, their resultant, the offspring, may reasonably be
expected to deviate but little from a course parallel to either, or to both.
Represent the reason of the law to ourselves by what physical metaphor
or analogy we will, however, the great matter is to apprehend its
existence and the importance of the consequences deducible from it.
For things which are like to the same are like to one another; and if; in
a great series of generations, every offspring is like its parent, it follows
that all the offspring and all the parents must be like one another; and
that, given an original parental stock, with the opportunity of
undisturbed multiplication, the law in question necessitates the
production, in course of time, of an indefinitely large group, the whole
of whose members are at once very similar and are blood relations,
having descended from the same parent, or pair of parents. The proof
that all the members of any given group of animals, or plants, had thus
descended, would be ordinarily considered sufficient to entitle them to
the rank of physiological species, for most physiologists consider
species to be definable as "the offspring of a single primitive stock."

But though it is quite true that all those groups we call species 'may',
according to the known laws of reproduction, have descended from a
single stock, and though it is very likely they really have done so, yet
this conclusion rests