[{202}] The effects of crossing is much more strongly stated here than in the Origin. See Ed. i. p. 20, vi. p. 23, where indeed the opposite point of view is given. His change of opinion may be due to his work on pigeons. The whole of the discussion on crossing corresponds to Chapter VIII of the Origin, Ed. i. rather than to anything in the earlier part of the book.
[{203}] The parallelism between the effects of a cross and the effects of conditions is given from a different point of view in the Origin, Ed. i. p. 266, vi. p. 391. See the experimental evidence for this important principle in the author’s work on Cross and Self-Fertilisation. Professor Bateson has suggested that the experiments should be repeated with gametically pure plants.
[{204}] The so-called Knight-Darwin Law is often misunderstood. See Goebel in Darwin and Modern Science, 1909, p. 419; also F. Darwin, Nature, Oct. 27, 1898.
[{205}] Pallas’ theory is discussed in the Origin, Ed. i. pp. 253, 254, vi. p. 374.
[{206}] See Darwin’s paper on the fertility of hybrids from the common and Chinese goose in Nature, Jan. 1, 1880.
[{207}] Origin, Ed. i. p. 19, vi. p. 22.
[{208}] Var. under Dom., Ed. ii. vol. II. p. 211.
[{209}] This discussion corresponds to the Origin, Ed. i. pp. 11 and 143, vi. pp. 13 and 177.
[{210}] See Origin, Ed. i. p. 7, vi. p. 7.
[{211}] «Note in the original.» “Isidore G. St Hilaire insists that breeding in captivity essential element. Schleiden on alkalies. «See Var. under Dom., Ed. ii. vol. II. p. 244, note 10.» What is it in domestication which causes variation?”