[251] Republished in Ostwald's _Kla.s.siker der exakten Wissenschaften_, No. 176, Leipzig, 1910. References in the text are to the original pagination.

[252] _Symbolae ad ovi avium historiam_.

[253] _De ovi mammalium et hominis genesi_.

[254] _De mulierum organis_, 1672.

[255] _Ann. Sci. nat._, iii., p. 135, 1842.

[256] _Recherches sur la generation des Mammiferes_.

Report by Academy Committee. _Ann. Sci. nat._ (2) (_Zool._) ii., pp. 1-18, 1834; also _Embryogenie comparee_, 1837.

[257] _Lond. and Edin. Phil. Mag._ (3) vii., 1835; _Phil.

Trans._ 1837.

[258] _Handbuch der Enfwickelungsgeschichte_, 1835, and Muller's _Archiv_, 1836.

[259] _Prodromus historiae generationis hominis atque animalium_, Lipsiae, 1836.

[260] Muller's _Archiv_, 1837.

[261] Sachs, _History of Botany_, Book ii.

[262] _Ann. Sci. nat._, i., pp. 110-14, 1824. Swammerdam is said to have observed the 2-celled stage in the egg of the frog (_Bibl. Nat._, 1752), and Rosel v. Rosenhof the same stage in the tree-frog (_Hist. nat. ranarum nostratium_, 1758).

[263] _Developpement de la grenouille commune_, Milan, 1826. _Biblioteca italiana_, lxxix., 1836, and Muller's _Archiv_, 1836. Aga.s.siz is said by Vogt (1842) to have seen segmentation in the Perch as early as 1831.

[264] Muller's _Archiv_, 1836.

[265] In Burdach, _Die Physiologie als Erfahrungswissenschaft_, 2nd Ed., vol. ii.

[266] Wiegmann's _Archiv_, 1837.

[267] _Bericht Versamml. deutsch. Naturf. in Prag_, 1837.

[268] _Bericht Versamm. deutsch. Naturf. in Freiburg_, 1838. Later in his _Entw. d. Wirbelth_., and in his papers on the development of the rabbit.

[269] _Phil. Trans._, 1839. See particularly Pl. vi., figs. 105-12.

[270] _Embryologie des Salmones_ 1842.

[271] Muller's _Archiv_, 1847.

[272] _C.R. Acad. Sci._, x.x.x., p. 638.

[273] See review by Leydig in _Isis_, 1848, pp. 161-193.

[274] Muller's _Archiv_, pp. 89-102, 1841.

[275] _De evolution Stronzyli auric. el Ascaridis ac.u.m._, Erlangen, 1841.

[276] Muller's _Archiv_, pp. 66-141, 1843.

[277] _Entwickelungsgeschichte der Cephalopoden_, Zurich, 1844.

[278] _Froriep's Notizen_, No. 800, 1846.

[279] _Isis_, 1848.

[280] Muller's _Archiv_, p. 47, 1852, also 1854 and 1858.

[281] See particularly Plate IX., figs. 3-7.

[282] _Hist.-krit. Bemerkungen zu den neuesten Mittheilungen u. d. erste Entwickelung d.

Saugethiereier_, Munchen, 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. Raderthiere_, 1854.

[286] _Arch f. path. Anat. Phys._, vii., pp. 1-39, 1854.

Also in his _Beitrage 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.