ating to this view have been held by the leading advocates of
the cell doctrine, and have beyond question been the inspiration of the
development of that doctrine.

But certainly no such conception of the significance of cell structure
would longer be held. In spite of the fact that the egg is a single
cell, it is impossible to avoid the belief that in some way it contains
the starfish. We need not, of course, think of it as containing the
structure of a starfish, but we are forced to conclude that in some way
its structure is such that it contains the starfish potentially. The
relation of its parts and the forces therein are such that, when placed
under proper conditions, it develops into a starfish. Another egg placed
under identical conditions will develop into a sea urchin, and another
into an oyster. If these three eggs have the power of developing into
three different animals under identical conditions, it is evident that
they must have corresponding differences in spite of the fact that each
is a single cell. Each must in some way contain its corresponding adult.
In other words, the organization must be within the cells, and hence not
simply produced by the associations of cells.

Over this subject there has been a deal of puzzling and not a little
experimentation. The presence of some sort of organization in the egg is
clear--but what is meant by this statement is not quite so clear. Is
this adult organization in the whole egg or only in its nucleus, and
especially in the chromosomes which, as we have seen, contain the
hereditary traits? When the egg begins to divide does each of the first
two cells still contain potentially the organization of the whole adult,
or only one half of it? Is the development of the egg simply the
unfolding of some structure already present; or is the structure
constantly developing into more and more complicated conditions owing
to the bringing of its parts into new relations? To answer these
questions experimenters have been engaged in dividing developing eggs
into pieces to determine what powers are still possessed by the
fragments. The results of such experiments are as yet rather
conflicting, but it is evident enough from them that we can no longer
look upon the egg cell as a simple undifferentiated cell. In some way it
already contains the characters of the adult, and when we remember that
the characters of the adult which are to be developed from the egg are
already determined