Mr. Henslow informs me that he has long held these views, but, as far as he knows, alone. Mr. Grant Allen, however, set forth a similar theory in his Vignettes from Nature (p. 15) and more fully in The Colours of Flowers (chap. v.), where he develops it fully and uses similar arguments to those of Mr. Henslow.
[156] H. Müller gives ample proof of this in his Fertilisation of Flowers.
[157] Cross-and Self-Fertilisation, p. 27.
[158] Animals and Plants, vol. ii. p. 145.
[159] Müller's Fertilisation of Flowers, pp. 448, 455. Other cases of recent degradation and readaptation to insect-fertilisation are given by Professor Henslow (see footnote, p. 324).
[160] The Colour Sense, by Grant Allen, p. 95.
[161] The Colour Sense, chap. ix.
[162] See Origin of Species, sixth edition, p. 220.