Skeleton, atrophy of, in the aged, 29 Sleep, and anæmia of brain, 122 and auto-intoxication, 120 and death compared, 125 Sleepiness, compared with hunger, 125 Sleeping-sickness, 124 Small-pox, and mortality rates, 144 Smell, analysis of, 243 Smell, rudimentary organs of sense of, 187 Smoking and longevity, 93 Social animals, 214, 220 _et seq._ Socialism, 228, 229 Society _v._ the individual, 223 _et seq._ Society, and morality, 306 Sociology, dependent on biology, 231 Sollier, Dr., on sensations at death, 130 Solomon, quotation from “Ecclesiastes,” 233 Somnambulism, analysis of, 200 _et seq._ Sorbose, fermentation of, 106 Soured milk, use of, 171, 181, 182 Sparrow, fecundity of, 58 Spencer, Herbert, criticism of Kant, 310 criticism of socialism, 230 theory of morality, 316, 322, 324, 327 Spermatozoa, in old age, 35 Spermine, 139, 140 Stadelmann, on lactic acid in diabetes, 170 Statistics on suicide, 3 Stature, in old age, 8, 9 Stein, Mde. von, 267, 268, 273 Steller’s sea-cow, 213 Stern, M., on disinfection of intestine, 156 Stohmann, on digestion in sheep, 74 Stoics, 309 Stragesco, Dr., on digestion in mammals, 63 Strasburger, on disinfection of intestine, 156, 157 on microbes in constipation, 70 Suicide, 3, 4, 237, 238, 265, 311 Sully-Prudhomme, definition of morality, 303 Suprarenal capsules, and atheroma, 32 Swimming, instinctive power of, 197, 198, 207 Syphilis, 31, 37, 145, 146, 302, 304 Switzerland, centenarians rare in, 91 Tanacol, as an intestinal antiseptic, 156 Taoism and immortality, 137, 138 Taste, analysis of, 243 Tavel, M., operations on large intestine, 152 _et seq._ Taylor, Bayard, translation of _Faust_, 285 Termites, 220, 221 Testis, emulsion of, as used by Brown-Séquard, 139 resistance of, to senescence, 35 Thanatology, 131 Theophrastus, 132 Thymol, as an intestinal antiseptic, 157 Thyroid, effects of extirpation of, 32, 33, 34 _Timon of Athens_, quotation from, 307 Tissier, Dr., on _Bacillus bifidus_, 161 on use of lactic microbes, 181 Tissier, and Martelly, on putrid food, 164 Tobacco and longevity, 93 Tokarsky, on natural death, 126 Tolstoi, and death, 94 “Death of Ivan Ilyitch,” 318 Tortoise, 11, 12, 13, 51 Touch, sense of, in the blind, 257 Troubat, M., on instinctive swimming, 198 Trees, age and death of, 96, 97, 98 _Trypanosoma_, 124 Unicellular organisms, death of, 95 Urine, analysis of, in a centenarian, 7 Utilitarianism, 305 Vacherot, criticism of Kant, 313 Varenetz, 172 Vascular glands, relation to old age, 33, 34 Verworn, Max, on death in infusoria, 95 Vinegar, in preservation of food, 165 Vivisection, 301 Voisin, M., criticism of neuronophagy, 20 Voltaire, 92, 235 Volz, on swimming power of gibbons, 198 Wales, Mr., quotation from Riley, 174