m of the
chemists; or is it not rather the servant of a higher regulatory power?
Johannes Mueller, who was Reichert's master, had in his _Physiology_[297]
argued splendidly for the existence of a creative force which guides and
rules development, and brings to pass that unity and harmony of
composition which distinguish living things from inorganic products.
Reichert sought in vain in the writings of the biological "atomists" for
any smallest recognition of these broader characteristics of living
things upon which Mueller had rightly laid stress. For the atomists the
cell was the only element of form; they ignored the combination of cells
to form tissues, of tissues to form organs, of organs to form an
organism. For the morphologists the cell was one element among many, and
the lowest of all.

The difference of attitude is clearly shown if we consider from the two
points of view a complicated organ-system such as the central nervous
system. The atomist sees in this a mere aggregate of cells or at the
most of groups of cells. "The morphologist," on the other hand, "sees in
the central nervous system a _proximate_ element in the composition of
the body--a primitive organ. From this point of view he apprehends and
judges its morphological relations with, in the first place, the other
co-ordinated primitive organs in the system as a whole; in all this the
cells remain in the background, and have nothing to do directly with the
determination of these morphological relations" (p. 6). Within the
nervous system there are separate organs which stand to one another in a
definite morphological and functional relationship. These organs are, it
is true, composed of cells; but between the form and connections of
these organs and the cells which compose them there is no direct and
necessary relation (p. 6). It is true that the cell is the ultimate
element of organic form, and that all development takes place by
multiplication and form-change of cells. Yet is the cell in all this not
independent of the unity of the developing embryo, and what the cells
produce, they produce, so to speak, not of their own free will, nor by
chance, but under the guiding influence of the unity of the whole, and
in a certain measure as its agents (p. 7). The atomists will not admit
the truth of this; they see in development nothing more than a process
of the form-change and multiplication of cells. The full meaning of
development escapes them, for they tak