Mittheilungen ue. d. erste Entwickelung d.
Saeugethiereier_, Muenchen, 1877.

[283] _Monatsber. Akad. Wiss. Berlin_, 1851.

[284] _Zur Lehre von Generationswechsel u. d. Fortpflanzen
d. Medusen u. Polypen_.

[285] _U. d. Bau u. d. system. Stellung d. Raederthiere_,
1854.

[286] _Arch f. path. Anat. Phys._, vii., pp. 1-39, 1854.
Also in his _Beitraege z. spec. Path. u. Therapie_.

[287] _Die Cellularpathologie_, Berlin, 1858.

[288] _Lehrbuch der Histologie_, 1857.

[289] _Ann, Sci. nat._ (2) iii., pp. 108-9 and pp. 312-4,
1835. Also iv, pp. 343-77.

[290] 1839 or 1840.

[2913] _Nova Acta Acad. Leop._, xxii., 1850. Trans. in 1853
for Ray Society.

[292] _Arch. f. Anat. u. Physiol._, pp. 1-27, 1861.

CHAPTER XII

THE CLOSE OF THE PRE-EVOLUTIONARY PERIOD

The influence of the cell-theory on morphology was not altogether happy.
The cell-theory was from the first physiological; cells were looked upon
as centres of force rather than elements of form, and the explanation of
all the activities of the organism was sought in the action of these
separate dynamic centres. There resulted a certain loss of feeling for
the problems of form. The organism was seen no longer as a cunningly
constructed complex of organs, tissues and cells; it had become a mere
cell-aggregate; the higher elements of form were disregarded and
ignored.

We have seen this physiological attitude expressed with the utmost
clearness by the founder of the cell-theory himself; we shall see the
same attitude taken up by most of his successors. Thus Vogt, who was
later to become one of the protagonists of materialism in Germany,
developed in his memoir on the embryology of _Coregonus_[293] the theory
of the independent or individual life of the cell. "Each cell," he
wrote, "represents in some measure a separate organism, and while their
development necessarily conforms to the general plan and the particular
tendencies of the parent organism, they nevertheless each follow their
own particular tendency and do not lose their independence until, by
reason of the metamorphoses which they undergo, they lose their cellular
nature" (p. 275).

And again, "... we are obliged to admit the existence in the cell of an
independent life, which makes its development self-sufficient.... Each
cell consequently represents a little independent organism, which
assimilates foreign substances,