[287] Spencer, Essays, ii. pp. 427, 430, 431. Some of the arguments of Spencer had been adduced by Barrington in his polemic against Buffon. Cf. Philosophical Transactions, 1773, pp. 262, 263 (Experiments on the singing of birds).
[288] Hudson, The Naturalist in La Plata, pp. 280 sq.
[289] A more detailed account of this question has been given in the author’s Förstudier till en konstfilosofi, pp. 29, 30.
[290] Espinas, Des sociétés animales, p. 328.
[291] For experiments proving the invigorating effects of colour-impression upon the animal organism, particularly upon insects, see Féré, Pathology of Emotions, p. 23.
[292] Brehm, Thierleben, iv. p. 20; cf. also Schneider, Der thierische Wille, p. 172; Espinas, l.c. p. 286; Groos, The Play of Animals, pp. 242-244.
[293] Groos, l.c. p. 242.
[294] Groos, The Play of Animals, pp. 244, 245; Die Spiele der Menschen, pp. 329-340.
[295] Darwin, The Descent of Man, ii. pp. 18, 94, 110, 137.
[296] Ibid. ii. p. 251. When advocating the Darwinian theory of sexual selection, Professor Poulton seems to use the notion “æsthetic appreciation” in this wide sense. Cf. Colours of Animals, p. 286.