Note 12 — Chapter XXIV · LAWS OF VARIATION—USE AND DISUSE, ETC.
Reading edition
‘Die Blutvertheilung, etc. der Organe,’ 1871, as quoted by Jaeger, ‘In Sachen Darwin’s,’ 1874, p. 48. See also H. Spencer ‘The Principles of Biology,’ vol. ii. 1866, chap. 3-5.