Self-fertilisation, i. 169, 297, ii. 46

“Shall we have Common Sense?” Sleeper’s, ii. 98, 99

Sharpe, Mr. J.W., reminiscences of Wallace, ii. 107-9

Shells, Lyell on, ii. 24

Shipley, Dr. A.E., and Wallace medallion in Westminster Abbey, ii. 253

Shrewsbury Grammar School, Darwin and, i. 12, 15

Sidgwick, Prof, and Mrs. H., telepathic experiments by, ii. 199, 200;
  Wallace’s remarks on, 200-1

“Siege of the South Pole,” Mill’s, ii. 82

Silk, George, i. 52, 87;
  Wallace’s friendship with, 10;
  walking tour in Switzerland with Wallace, 35

Sims, Mrs. (sister of A.R.  Wallace), i. 30, 44, 56, 60, 62, 64, 85

——­ Thomas, i. 63, 73

Singapore, Wallace at, i. 36

Slade, prosecution of, ii. 197

Sleeper, George W., ii. 98, 99, 100

Smedley, Mr. E., ii. 83, 100, 163, 175, 215

Smith, Dr. Edwin, ii. 210

“Social Environment and Moral Progress,” Wallace’s, ii. 104, 144-5, 250

“——­ Statics,” Spencer’s, i. 123, 150, ii. 143

Socialism, Wallace’s first lessons in, and later views of, i. 15, 16,
    ii. 139 et seq.;
  “individualistic,” 114;
  Wallace’s definition of, 152

Society for Psychical Research, foundation of, ii. 196

“Sociology, Principles of,” i. 126

“——­ Study of,” Spencer’s, i. 283

Solar nebula, lecture by Sir R. Ball on, ii. 174

——­ system, central position of, ii. 171

South America, fauna of, ii. 10

Special creation, i. 189 (note), 190, 192, ii. 23, 185

Species, mutability of, i. 78, 137;
  law of introduction of, 96, 101-2;
  extinction of, 98.
  (See also Selection, natural)

Spencer, Herbert, birth of, i. 5;
  and Evolution, 122, 123;
  arguments with Huxley on Evolution, 123;
  sends Darwin a copy of his Essays, 124;
  suggests “survival of the fittest” as alternative to “natural
    selection,” 125, 171;
  Wallace’s relations with, 125;
  Darwin’s approval of “survival of the fittest,” 174;
  autobiography of, ii. 211

——­ letters from: 
  on “Origin of the Races of Man,” ii. 18;
  on theory of flight, 27-8;
  on “Darwinism,” 47;
  on Lord Salisbury’s view of Natural Selection, 59, 60, 65;
  on Land Nationalisation Society, 154;
  on “Progress and Poverty,” etc., 154-5

Spilosoma menthastri, i. 179

Spiritualism, Wallace’s belief in, ii. 122, 167, 178, 181 et seq.,
    239-40;
  Huxley on, 187;
  Lord Avebury on, 212

Spiritualists, Association of, ii. 198, 199

Spontaneous generation, i. 274

Spruce, Mr., i. 150, 161, 166, 232

Stanley, Dean, at Linlathen, ii. 228

Stephens’ “Illustrations of British Insects,” i. 23 (note)