[143] To Lyell, October 1, 1861, More Letters, vol. II, p. 191.
[144] Zur Naturwissenschaft, Einzelne Betrachtungen und Aphorismen, section III.
[145] To Hooker, December 10, 1866, Life, vol. II, p. 239.
[146] To Hooker, May 2, 1857, Life, vol. I, p. 454.
[147] Darwiniana, p. 246.
[148] To De Candolle, January 14, 1863, More Letters, vol. I, p. 234.
[149] To Hooker, April 1, 1864, More Letters, vol. II, p. 330.
[150] To Hooker, April, 1857, Life, vol. I, p. 450.
[151] To Hooker, March 7, 1855, Life, vol. I, p. 405.
[152] To Hooker, July 30, 1856, Life, vol. I, p. 439.