conclusions respecting the relation of the structure of the
flower to the insect world. This Gärtner entirely failed to do,
and hence in this case also it was reserved for Darwin's
wonderful talent for combination to sum up the product of the
investigations of a hundred years, and to blend Koelreuter's,
Knight's, Herbert's, and Gärtner's results with Sprengel's
theory of flowers into a living whole in such a manner, that
now all the physiological arrangements in the flower have
become intelligible both in their relations to fertilisation, and
in their dependence on the natural conditions under which
pollination takes place without the aid of man. Here, as in
morphology and systematic botany, Darwin found the premisses given and drew the conclusion from them; here too the certainty of his theory rests on the results of the best
observers, on investigations which find in that theory their
necessary logical and historical consummation.
7. Microscopic investigation into the processes of fertilisation in the phanerogams; pollen-tube and egg-cells[1]. 1830-1850.
Those who were convinced of the sexuality of plants had endeavoured as early as the previous century to form some idea with the help of the microscope of the way in which the pollen effects the formation of the embryo in the ovule. We may pass over Morland's and Geoffrey's very rude attempts in this direction; Needham (1750), Jussieu, Linnaeus, Gleichcn, and Hedwig imagined that the pollen-grain bursts upon the stigma, and that the granules it contains make their way down-
- ↑ The more important works referred to in this section are Robert Brown's 'Miscellaneous Writings,' edited by Bennett, 1866-67; von Mohl on G. Amici, in the 'Dotanische Zeitung,' 1863, Beilage, p. 7; Schleiden, 'Ueber die Bildung des Lichens und Entstchung des Embryos,' in 'Nova Acta Academiae Leopoldinensis,' 1839, vol. xi, Abtheilung, i; Hofmeister, 'Zur Uebersicht der Geschichte von der Lehre der Pflanzenbefrachtting,' in 'Flora' of 1867, p. 119.
