The Principles of Biology, Volume 1 (of 2)

by Herbert Spencer

Ibid., p. 212.

[82]

Ibid., p. 266.

[83]

Prin. of. Phys., p. 267.

[84]

Ibid., p. 276.

[85]

Ibid., 2nd edit., p. 115.

[86]