Conklin, Edwin Grant, _The Direction of Human Evolution_. _Evolution._ Darwin, Emma, _A Century of Family Letters_, two volumes. _Family Letters._ Darwin, _The Life and Letters of Charles Darwin_, two volumes. _Life._ De Vries, Hugo, _Species and Varieties, Their Origin by Mutation_. _Species and Varieties._ Goncourts, Edmond et Jules, _Journal des Goncourts_, nine volumes. _Goncourts, Journal._ Gray, Asa, _Letters of_, edited by Jane Loring Gray, two volumes. Gray _Letters._ Grant Duff, Sir Mountstuart E., _Notes from a Diary_, fourteen volumes, 1851-1901. Grant Duff. Huxley, Thomas H., _Darwiniana_ (the second volume of Collected Essays). _Darwiniana._ Huxley, Thomas H., _Life and Letters of_, by his son Leonard, two volumes. Huxley, _Life._ Lull Richard, Harry Burr Ferris, George Howard Parker, James Rowland Angell, Albert Galloway Keller, Edwin Grant Conklin, _The Evolution of Man_. Lull. Morgan, Thomas Hunt, _Evolution and Adaptation_. _Evolution and Adaptation._ Osborn, Henry Fairfield, _The Earth Speaks to Bryan_. _The Earth Speaks._ Osborn, _From the Greeks to Darwin_. _Greeks to Darwin._ Osborn, Henry Fairfield, _Impressions of Great Naturalists_. _Great Naturalists._ Parker, George Howard, _What Evolution Is_. _What Evolution Is._ Pearson, Karl, _The Grammar of Science_. _Grammar of Science._ Thoreau, Henry, _Journal_, fourteen volumes. _Journal._ _Vallery-Radot, Pasteur._ _Vallery-Radot, Pasteur._ Wallace, Alfred Russell, _My Life_, two volumes. Wallace, _Life_. Whitehead, Alfred North, _Science and_ _the Modern World_. _Science and the Modern World._ NOTES CHAPTER I: THE OBSERVER [1] _Journal des Goncourts_, May 1, 1857, vol. I, p. 182. [2] Ben Jonson, _The Poetaster_, act II, scene 1. [3] _Sentimental Journey_, ‘In the Street.’ [4] _Portraits Littéraires_, vol. III, p. 546. [5] _Expression_, p. 80. [6] Thoreau, _Journal_, vol. VII, p. 46. [7] Gray, to Darwin, May 18, 1862, Gray, _Letters_, vol. II, p. 481. [8] _Great Naturalists_, p. 51. [9] _More Letters_, vol. I, p. 72. [10] _Life_, vol. I, p. 83. [11] To Farrar, November 26, 1868, _Life_, vol. II, p. 453. [12] To Hooker, 1867, _More Letters_, vol. II, p. 6. [13] To Lyell, June 1, 1867, _Life_, vol. II, p. 248. [14] To Wilson, April 29, 1878, _More Letters_, vol. II, p. 421. [15] To Galton, November, 1879, _Life_, vol. II, p. 414. [16] To Lyell, March 17, 1863, _Life_, vol. II, p. 201. [17] To Galton, November 8, 1872, _More Letters_, vol. II, p. 108. [18] _Expression_, p. 184. [19] To Dr. Ogle, March 12, 1871, _Life_, vol. II, p. 321. [20] _More Letters_, vol. I, p. 4. [21] To Jenyns, October 17, 1846, _Life_, vol. I, p. 396. [22] _Beagle Journal_, p. 282. [23] To Gray, June 3, 1874, _Life_, vol. II, p. 457. [24] To Hooker, December 11, 1860, _Life_, vol. II, p. 148. [25] To Scott, July 2, 1863, _More Letters_, vol. II, p. 323. [26] To Horner, January, 1847, _More Letters_, vol. II, p. 224. [27] _Expression_, p. 12.