Neuron theory, 208. Neuropathic constitution, expression of, 241. Neuropathic defects, carriers of, 253. Neuter insects, heredity in, 136, 137. New characters, origin of, 138. Newman, 56. Nicloux, 172. Night-blindness, 65. Nilsson-Ehle, 88, 89. Noguchi, 186. Nucleolus, 31. Nucleus, structure of, 31. Nulliplex character, 80, 100. Obesity, 120, 154. Offspring: from one parent only, 5; different from either parent, 12. Oöcyte, primary, secondary, 44. Oögenesis, 44. Oögonia, 44. Optic nerve, atrophy of, 64. Organs, formation of, 36. Origin of sex cells, 12, 36. Ovaries, transplantation of, 134. Ovum, 26, 40. Paralysis, general, 186. Paranoia, 279. Parent-body and germ distinct, 12. Parenthood, cultivation of wholesome sentiment toward, 336. Paresis: 186; and crime, 279. Parthenogenesis, 6. Patterson, 56. Paul, 163. Pearson, 150, 151, 179, 296, 307. Peas, 68, 82. Performance tests, 256. Peron, 133. Personality determined by heredity, 2, 195. Peterson, 242. Phenotype, 86. Phillips, 134, 135. Phototropism, 198. Pinard, 165. Pineys, the, 271. Plato, 290. Poellman, 271. Polar bodies, 44, 45. Polydactyly, 108. Potato-beetle, production of variations in, 125. Potts, 292. Predisposition to disease, 148. Pregnancy, neglect of mothers during, 165. Prenatal care: 336; infection, 147; influence, 11, 159, 162. Prenuptial medical inspection desirable, 336. Presence and absence theory: 78; formulæ for man, 99. Primrose, experiments on, 125. Principles, Mendelian, 68. Prisoners, many mentally subnormal, 266. Pronucleus, 47. Protective coloration, not of somatic origin, 135, 136. Protoplasm, germinal, 39. Psychical development, 196, 203, 205, 206, 213, 215. Pyramidal tracts, 214. Quagga hybrid, 10. Race amalgamation: 297, 298; deterioration, in a selected population, 303. Racial degeneracy, not curable by improved environment alone, 294. Ratio: the 1:2:1, 73; the 3:1, 77; the 9:3:3:1, 85; the 27:9:9:9:3:3:3:1, 87; the 15:1, 88; the 63:1, 90. Rational behavior, 205, 206. Reason, 206. Recessiveness: 74; in man, 115. Records of family traits desirable, 337. Reduction division, 41, 42. Reflexes, 203. Regression, law of, 17. Renault, 172. Rentoul, 232. Reproduction: asexual, 6, 26; sexual, 26; sexual and variation, 139. Reproductive cells, 27, 28, 29. Responsibility for conduct, 195. Rest, importance of, in pregnancy, 165. Reversion: 7, 8; and atavism, 8; in guinea-chicken hybrids, 8. Rheotropism, 198. Rheumatism, 154. Ritter, 143. Rogers, 246, 272. Romanes, 133. Rosanoff, 243. Rossolimo, 256. Rudin, 243. Salpingectomy, 322. Sanford, 205. St. Vitus' dance, 117. Schulze, 24. Schuster, 296. Sclerosis, multiple, 64, 117.