Acad. des Sciences,' 1790, p. 209.

[329] 'On the Varieties of Wheat,' p. 52.

[330] Mr. Spencer has fully and ably discussed this whole subject in his
'Principles of Biology,' 1864, vol. ii. ch. x. In the first edition of my
'Origin of Species,' 1859, p. 267, I spoke of the good effects from slight
changes in the conditions of life and from cross-breeding, and of the evil
effects from great changes in the conditions and from crossing widely
distinct forms, as a series of facts "connected together by some common but
unknown bond, which is essentially related to the principle of life."

[331] 'Essais de Zoologie Generale,' 1841, p. 256.

[332] Du Rut, 'Annales du Museum,' 1807, tom. ix. p. 120.

[333] 'Saeugethiere von Paraguay,' 1830, s. 49, 106, 118, 124, 201, 208,
249, 265, 327.

[334] 'The Naturalist on the Amazons,' 1863, vol. i. pp. 99, 193; vol. ii.
p. 113.

[335] 'Embassy to the Court of Ava,' vol. i. p. 534.

[336] 'Journal,' vol. i. p. 213.

[337] 'Saeugethiere,' s. 327.

[338] On the Breeding of the larger Felidae, 'Proc. Zoolog. Soc.,' 1861, p.
140.

[339] Sleeman's 'Rambles in India,' vol. ii. p. 10.

[340] Wiegmann's 'Archif fuer Naturgesch.,' 1837, s. 162.

[341] Rengger, 'Saeugethiere,' &c., s. 276. On the parentage of the
guinea-pig, _see_ also Isid. Geoffroy St. Hilaire, 'Hist. Nat. Gen.'

[342] Although the existence of the _Leporides_, as described by Dr. Broca
('Journal de Phys.,' tom. ii. p. 370), is now positively denied, yet Dr.
Pigeaux ('Annals and Mag. of Nat. Hist.,' vol. xx., 1867, p. 75) affirms
that the hare and rabbit have produced hybrids.

[343] 'Quadrupeds of North America,' by Audubon and Bachman, 1846, p. 268.

[344] Loudon's 'Mag. of Nat. Hist.,' vol. ix., 1836, p. 571; Audubon and
Bachman's 'Quadrupeds of North America,' p. 221.

[345] Flourens, 'De l'Instinct,' &c., 1845, p. 88.

[346] _See_ 'Annual Reports Zoolog. Soc.,' 1855, 1858, 1863, 1864; 'Times'
newspaper, Aug. 10th, 1847; Flourens, 'De l'Instinct,' p. 85.

[347] 'Saeugethiere,' &c., s. 34, 49.

[348] Art. Brazil, 'Penny Cyclop.,' p. 363.

[349] 'The Naturalist on the River Amazon,' vol. i. p. 99.

[350] 'Encyclop. of Rural Sports,' p. 691.

[351] According to Sir A. Burnes ('Cabool,' &c., p. 51), eight species are
used for hawking in Scinde.

[352] Loudon's 'Mag. of Nat. Hist.,' vol. vi., 1833, p. 110.

[353] F. Cuvier, 'Annal. du Museum,' tom. ix. p. 128.

[354] 'The Zoologist,' vol. vii.-vii