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Quarterly Journal of Microscopical Science, Vol s3-94, 407-440, Copyright © 1953 by Company of Biologists
1 Department of Zoology and Comparative Anatomy, Oxford
In the first half of the nineteenth century it was commonly supposed that new cells arose either exogenously, outside pre-existing cells, or endogenously, from small rudiments that appeared within pre-existing cells and gradually grew larger. The theory of exogeny had been founded by Wolff (1759), and was supported especially by Link (1807), Schwann (1839), and Vogt (1842). The theory of endogeny, which had been hinted at by various writers in early times, obtained the backing of a very large literature. Its chief advocates were Raspail (1825, &c), Turpin (1827, &c), Schleiden (1838), Kölliker (1843-4), and Goodsir (1845).
That cells do not arise exogenously or endogenously, but are produced by the division of pre-existing cells, was at last realized by the convergence of studies made in three separate fields, as follows :
(1) Trembley (1746, &c), Morren (1830, 1836), Ehrenberg (1830, 1832, 1838), and others noticed how protists multiply.
(2) Dumortier (1832), Mohl (1837), and Meyen (1838) watched the partitioning of the cells of filamentous algae.
(3) Several observers studied the cleavage of eggs and at last revealed that this was a process of cell-division (Prevost and Dumas (1824), von Siebold (1837), Barry (1839), Reichert (1840), Bagge (1841), Bergmann (1841-2)).
Nägeli (1844, 1846) also made an important study of cell-division in all the main groups ofplants (except bacteria), but used an unfortunate nomenclature that tended to obscure the truenature of the process.
Remak (1852 and 1855) and Virchow (1852, 1855, 1859) made general statements to the effect that division is the standard method by which cells multiply. The writings of Remak on this subject were much more weighty than those of Virchow.
