[45] As stated by Mr. Orton, in his ‘Physiology of Breeding,’ p. 12.
[46] M. E. de Selys-Longchamps refers (‘Bulletin Acad. Roy. de Bruxelles,’ tom. xii. No. 10) to more than seven of these hybrids shot in Switzerland and France. M. Deby asserts (‘Zoologist,’ vol. v., 1845-46, p. 1254) that several have been shot in various parts of Belgium and Northern France. Audubon (‘Ornitholog. Biography,’ vol. iii. p. 168), speaking of these hybrids, says that, in North America, they “now and then wander off and become quite wild.”
[47] ‘Journal of Researches,’ 1845, p. 71.
[48] ‘Expedition to the Zambesi,’ 1865, pp. 25, 150.
[49] Dr. P. Broca, on ‘Hybridity in the Genus Homo,’ Eng. translat., 1864, p. 39.
[50] ‘Nouvelles Archives du Muséum,’ tom. i. p. 151.
[51] ‘Bastarderzeugung,’ s. 582, 438, etc.
[52] ‘Die Bastardbefruchtung . . . der Weiden,’ 1865, s. 23. For Gärtner’s remarks on this head, see ‘Bastarderzeugung,’ s. 474, 582.
[53] Prof. Weismann, in his very curious essay on the different forms produced by the same species of butterfly at different seasons (‘Saison-Dimorphismus der Schmetterlinge,’ pp. 27, 28), has come to a similar conclusion, namely, that any cause which disturbs the organisation, such as the exposure of the cocoons to heat or even to much shaking, gives a tendency to reversion.
[54] Yarrell, ‘Phil. Transact.,’ 1827, p. 268; Dr. Hamilton, in ‘Proc. Zoolog. Soc.,’ 1862, p. 23.