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, 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).