s of unorganized but organizable matter--either the body of
one of the lowest living forms, or the germ of one of the higher.
Consider its circumstances. It is immersed in water or air; or it is
contained within a parent organism. Wherever placed, however, its outer
and inner parts stand differently related to surrounding
existences--nutriment, oxygen, and the various stimuli. But this is not
all. Whether it lies quiescent at the bottom of the water, whether it
moves through the water preserving some definite attitude, or whether it
is in the inside of an adult; it equally results that certain parts of
its surface are more directly exposed to surrounding agencies than other
parts--in some cases more exposed to light, heat, or oxygen, and in
others to the maternal tissues and their contents. The destruction of
its original equilibrium is therefore certain. It may take place in one
of two ways. Either the disturbing forces may be such as to overbalance
the affinities of the organic elements, in which case there results that
chaotic heterogeneity known as decomposition; or, as is ordinarily the
case, such changes are induced as do not destroy the organic compounds,
but only modify them: the parts most exposed to the modifying forces
being most modified. Hence result those first differentiations which
constitute incipient organization. From the point of view thus reached,
suppose we look at a few cases: neglecting for the present all
consideration of the tendency to assume the inherited type.

Note first what appear to be exceptions, as the _Amoeba_. In this
creature and its allies, the substance of the jelly-like body remains
throughout life unorganized--undergoes no permanent differentiations.
But this fact, which seems directly opposed to our inference, is really
one of the most significant evidences of its truth. For what is the
peculiarity of the Rhizopods, exemplified by the _Amoeba_? They
undergo perpetual and irregular changes of shape--they show no
persistent relations of parts. What lately formed a portion of the
interior is now protruded, and, as a temporary limb, is attached to some
object it happens to touch. What is now a part of the surface will
presently be drawn, along with the atom of nutriment sticking to it,
into the centre of the mass. Thus there is an unceasing interchange of
places; and the relations of inner and outer have no settled existence.
But by the hypothesis, it is only in virtue of their unli