Gesture, language of, 48 et seq., 66. Glass, 163. Goethe, 109, 134. Guyau, 166, 178. _Habere_, 79. Haeckel, 108. Hare, ruses of, 18. Hebrew, 69. Heinicke, 64. Helmholtz, 62. Heredity of acquired characters, 218. Hoeffding, 4, 136. Horwicz, 165, 166. Houzeau, 17, 18, 36. Huber, 55. Hume, 187, 190. Huxley, 10, 22, 212. Hybrids, 208. Hysterics, 127. Idealogues, 68. _Idées-forces_, 177. Identity, sense of, 6. Ideography, 53. Images, logic of, 26 et seq., 40; also 5 et seq., 111. Imagination, forms of, 112. Indifferent point, 163. Individual, notion of the, 204. Inference, 24, 26, 30. Infinity, 144. Intelligence, 87. Inventors, rôle of, 219. Iroquois, 74. Isolates, 17. James, W., 6, 9, 29, 30, 46, 80, 140, 149, 162, 175, 176, 194. Janet, 163. Kant, 137, 158, 175, 190. Kepler, 197, 202. Kirby, 55. Kleinpaul, 52. Kussmaul, 45, 46. Ladd, 7. Lamarck, 206. Language, origin of, 31 et seq., 54 et seq. Languages, natural organisms, 83; savage, 95 et seq. Laplace, 218. Lapp, 76. Law, origin of concept of, 194 et seq.; theoretical or ideal, 200. Laws, defined, 197; called by the names of their inventors, 198; vary in the course of evolution, 213. Lefèvre, A., 61. Leibnitz, 31, 129, 140, 214. Leroy, G., 18, 19, 30, 57. Lewes, 180. Liard, 142. Linnæus, 106, 210. Lobachévski, 156. Locke, 31. Lotze, 150, 151, 178. Lubbock, 20, 50, 55, 96. Mach, E., 148, 163, 164, 178, 202. Maclellan, 139. Magpie, 20, 21. Maine de Biran, 181. Mallery, Colonel, 49, 50, 51. Mariotte, 202. Mathematical faculty, the, 217. Mathematicians, 126. Mathematics, originated in observation, 148. Mayer, R., 191. Measure of quantity, 100. Memory, 132. Mill, John Stuart, 24, 25, 26, 34, 138, 151, 154, 155, 181, 191. Mimicry, language of, 52. Mind, the, 9, 216. Miracles, 186. Mivart, St. George, 48. Monkeys, intelligence of, 19. Montesquieu, 197. Morgan, C. Lloyd, 16, 30. Motion, psychology of, 182. Motor types, 112. Müller, Fr., 60. Müller, Max, 28, 39, 40, 59, 60, 69, 71, 74, 79, 80, 92. Münsterberg, 148, 163, 166, 167, 177. Muscular types, 112. Mussels, 84. Names, individual, appellative or general?, 32. Nativists, 149. Neanderthal anthropoid, 61. Neo-geometers, 157. Neretina, 7. Newton, 218, 219. Nichols, 139, 161, 164, 175. Noiré, L., 60. Nomenclature, 105 et seq. Nominalists, 122, 128. Normal time, 167. Nothing, the answer, 127 et seq. Number, concept of, history and theories of its origin, 137 et seq. Numbers, sequence of, 142 et seq.; nature of, 146. Numeration, in animals, 19; in the child, 35; its development, 98. Observations on general terms, 114 et seq. Oken, 108. Onomatopœia, 71, 72. Order, 211. Owen, Richard, 109. Painter, 117.