[341] Mental Physiol., § 124. The oft-cited case of soldiers not perceiving that they are wounded is of an analogous sort.
[342] Prof. J. M. Cattell made experiments to which we shall refer further on, on the degree to which reaction-times might be shortened by distracting or voluntarily concentrating the attention. He says of the latter series that "the averages show that the attention can be kept strained, that is, the centres kept in a state of unstable equilibrium, for one second" (Mind, xi, 240).
[343] Physiologische Optik, § 32.
[344] "'Genius,' says Helvetius, 'is nothing but a continued attention (une attention suivie).' 'Genius,' says Buffon, 'is only a protracted patience (une longue patience).' 'In the exact sciences, at least,' says Cuvier, 'it is the patience of a sound intellect, when invincible, which truly constitutes genius.' And Chesterfield has also observed that 'the power of applying an attention, steady and undissipated, to a single object, is the sure mark of a superior genius.'" (Hamilton: Lect. on Metaph., lecture xiv.)
[345] See, e.g., Ulrici: Leib u. Seele, ii, 28; Lotze: Metaphysik, § 273; Fechner, Revision d. Psychophysik, xix; G. E. Müller: Zur Theorie d. sinnl. Aufmerksamkeit, $ 1; Stumpf: Tonpsychologie, i, 71.
[346] Fechner, op. cit. p. 271.
[347] Tonpsychologie, i, p. 71.
[348] Compare, on clearness as the essential fruit of attention, Lotze's Metaphysic, § 273.
[349] Elements, part i, chap. ii.
[350] Physiol. Psych., 2d ed. ii, 226.