277;
  on Darwin’s “Expression of the Emotions,” 279;
  on invitation to undertake revision work for Darwin, 281, 282;
  on “Climbing Plants,” 285;
  on Darwin’s criticism of “Geographical Distribution,” 288, 294;
  on Darwin’s “Crossing Plants,” 296;
  on Darwin’s “Orchids,” 297;
  on Darwin’s “Forms of Flowers,” and glacial theory, 298;
  on sufficiency of Natural Selection, 300;
  on Epping Forest superintendency, 302, 303;
  on “Island Life,” 305, 306;
  on Darwin’s criticism of “Island Life,” 308;
  on Darwin’s “Movements of Plants,” 311;
  on land migration of plants, 311;
  on Civil List pension, 314, 315;
  on “Progress and Poverty,” 317;
  on Darwin’s “Earthworms,” 320

——­ ——­ ——­ letters to Sir Francis Darwin: 
  on Darwin’s “Life and Letters,” ii. 39;
  on descent with modification, 78;
  on mutation, 80

——­ ——­ ——­ letter to Mr. W.J.  Farmer, on final cause of varying
    colour of hairs, etc., ii. 101-2

——­ ——­ ——­ letter to Dr. W.B.  Hemsley, on insular floras, ii. 43-4

——­ ——­ ——­ letter to Rev. J.B.  Henderson, on Christianity, ii. 209

——­ ——­ ——­ letter to Sir J. Hooker, on Natural Selection, etc.,
    ii. 81-2

——­ ——­ ——­ letters to Huxley: 
  enclosing a copy of “The Scientific Aspect of the Supernatural,” ii. 187;
  on psychical research, 188

——­ ——­ ——­ letter to Mr. J. Hyder, on land nationalisation, ii. 161

——­ ——­ ——­ letter to Prof.  Knight, on immortality, ii. 178

——­ ——­ ——­ letter to Dr. Littledale, acknowledging birthday congratulations, ii. 136

——­ ——­ ——­ letters to Sir Oliver Lodge: 
  on proof of constant variability, and Lord Kelvin’s calculations,
    ii. 74-5;
  on principle of continuity, etc., 178-9;
  acknowledging Romanes’ lecture and criticising lectures by Mr.
    See, 179-80

——­ ——­ ——­ letter to Sir C. Lyell, on colour of man, ii. 29

——­ ——­ ——­ letters to Mr. J.W.  Marshall: 
  on Hudson’s observations and theories, ii. 53-4;
  conveying condolences, and views on a hereafter, 209;
  on his autobiography, 226

——­ ——­ ——­ letters to Prof.  Meldola: 
  on physiological selection, ii. 36-8;
  on Natural Selection, 41, 42-3;
  on Meldola’s controversy with Romanes, 50-1;
  on individual adaptability, 55-6;
  on “discontinuous variation,” 62-3;
  on Weismann’s “Germinal Selection,” 68-70;
  on Weismann’s doctrine of non-inheritance of acquired characters, 70-1;
  on Weismann’s “Germ Plasm,” 72;
  on Fisher’s “Physics of the Earth’s Crust,” 74;
  on Meldola’s offer to read Wallace’s paper at Royal Institute, 87-8

——­ ——­ ——­ letter to Mr. Ben.  R. Miller, on Sleeper’s “Shall we
    have Common Sense?” ii. 98-9

——­ ——­ ——­ letter to Mr. John (Lord) Morley, on Socialism, ii. 159