Nirvâna, Aurelius and, 175 Hartmann on, 186 Schopenhauer on, 182 meaning of, 155, 156, 157 Nordau, on old age, 234 on optimism, 192; on pain, 193 Nuttall and Thierfelder, on germ-free guinea-pigs, 249 Obstetrics, in ancient times, 300 Old age, Longet on, 234 Nordau on, 234 amelioration of, 254 in birds and mammals, 232, 233 characters of, 229, 230, 278, 294 morbidity of, 244 scientific study of, 228 serums in, 245, 246 Onanism, 35, 95, 96, 99 Optimism, Hammerling on, 191, 192 Nordau on, 192 Optimists generally old men, 117 Origin of man, due to sudden appearance of new characters, 57, 59 Ourangs, old age in, 233 Orchids, and fertilisation, 19, 20 Orthobiosis, the taste of science, 289 Ostwald, on love of humanity, 296 Ova, immortality of, 267 Pain, Nordau on, 193 _Palingenia_, swarming of, 272 Pantheism, of German poets, 195 Paradise, according to the Talmud, 143 of Chinese Buddhists, 149 _Paramecium_, conjugation of (figure), 231 division of (figure), 230 Parasites, late evolution of, 18 Parovaria, 80 Parrots, paucity of bacterial flora in, 253 Pasteur, as founder of modern scientific medicine, 209 Pasénadi, legend on immortality, 147 Pathology, of old age, 278 Patriotism, 295 _Pelopæus_, figure of, 34 Penis, os, in man and apes, 81 Personality, consciousness of, 160 Pessimism, Byron on, 177 Hartmann on, 183 Maeterlinck on, 191 Mailaender on, 187 Schopenhauer on, 177, 178, 179 and Buddhism, 176, 177 and disease, 206 and disharmony, 38 origin of, 176 value of, 194 and youth, 117 Pettenkofer, suicide of, 131 Pfeffer, on chemotaxis in cryptogams, 269 Pflüger, on prolonging life, 258 Pfungst, on meaning of Nirvâna, 156 Phagocytes, functions of, 239 inhibited by lactic acid, 255 and poisons, 247 sensibility of, 240 Phagocytosis, in old age, 244 in senility, 242 Philosophy, and death, 166 relation of, and religion, 166 tendency of, to become religious, 175 Phenol, production of by microbes, 251 _Pithecanthropus_, 50 Placenta, of man and apes, 46 Plague, cause of, 208 Plato, and nobility of man, 4 on pleasure, 6 views on death, 166, 167, 168 Pleasure, views of Plato and Aristotle on, 6 Plotin, on immortality, 175 Pollinia of orchids, 21 Politicians, incapacity of young, 295 Politics, compared with savage obstetrics, 300 Post-mortem examinations, 246, 289 Pregnancy, avoidance of, 101 Progress, Hartmann on, 185 Spencer on, 291 not uniform, 18 Protection, means for, amongst animals, 114 Protozoa, absence of death, 263 sensibility of, 268 Purgatory, in Taoism, 146 Putrefaction, in large intestine, 73, 254 Rabbits, and destruction of young, 34, 37 Reformation, 14 Regeneration, in brain, 277 in cells, 271 in vertebrates, 270