builds them up, and rejects those that
are useless; from this point of view the embryo can be compared up to a
certain point with a zoophyte stock, of which each polyp, while living
its own independent life, is yet incorporated in the common corm, which
impresses its distinctive character upon every polyp" (p. 293).

Classical expression was given to the "colonial theory" of the organism
by Virchow in his lectures on "Cellular Pathology."[294] For Virchow the
organism resolves itself into an assemblage of living centres, the
cells; the organism has no real existence as a unity, for there is no
one single centre from which its activities are ruled. Even the nervous
system, which appears to act as a co-ordinating centre, is itself an
aggregate of discrete cells. "A tree is a body of definite and orderly
composition, the ultimate elements of which, in every part of it, in
leaf and root, in stem and flower, are cellular elements--so also are
animal forms. _Every animal is a sum of vital units_, each of which
possesses the full characteristics of life. The character and the unity
of life cannot be found in one definite point of a higher organisation,
for example in the brain of man, but only in the definite, constantly
recurring disposition shown individually by each single element. It
follows that the composition of the major organism, the so-called
individual, must be likened to a kind of social arrangement or society,
in which a number of separate existences are dependent upon one another,
in such a way, however, that each element possesses its own particular
activity, and, although receiving the stimulus to activity from the
other elements, carries out its own task by its own powers" (2nd ed.,
pp. 12-13).

Analysis, decomposition, or disintegration of the organism is here
pushed to its extreme point, and the problem of recomposition, synthesis
and co-ordination shirked or forgotten.

The harmful influence of the cell-theory upon morphology did not pass
unnoticed by the broader-minded zoologists of the day. Virchow's earlier
paper[295] on the application of the cell-theory to physiology and
pathology called forth a vigorous protest from Reichert,[296] who
discussed in a very instructive way the contrast between the older
"systematic" and the newer "atomistic" attitude to living Nature.

Is it really true, he asks, that the cell is the dominant element in all
organisation; is the cell comparable in importance to the ato