_Dendrostoma_, 101 _Dentalium_, 144 Design, 4, 5 Determination of sex, in bees, 208 ff.; in phylloxerans, 210; in _Bonellia_, 215 Development of egg, 127 ff. de Vries, H., 6, 42, 154, 161, 347, 369 Dewitz, 93 Dieudonné, C., 334, 337 “Directive force,” 2 Disharmonies, 7 Divisibility of living matter, limits of, 148-151 Dominance, 230 Doncaster, L., 203 Dorfmeister, 303 Driesch, H., 4 ff., 128, 133, 136, 138 ff., 147, 150, 169 ff., 180 ff., 184 ff. _Drosophila ampelophila_, 204 ff., 237, 243, 322, 347, 366 Duclaux, E., 288, 289 v. Dungern, 80 Duration of life, 360 ff. Durham, 249 Dutrochet, 154 Dzierzon, 208 Ectoderm formation, 130 ff. Egg, as the future embryo, 8, 9, 70, 126, 151; artificial parthenogenesis of, 95 ff.; organisms from, 128 ff.; determining unity of organism, 151-152; chromosomes in, 198 ff. Egg structure, 129 ff.; influence of centrifugal force on, 135; and regulation, 139, 140, 141; and fluidity of protoplasm, 141 Ehrlich, 45, 322, 332 ff., 341; side-chain theory of, 88, 188 Eigenmann, 320, 323 ff. Electromotive forces, origin in living organs, 140 Engelmann, 357 Engler, 24 Entelechy, 4, 170, 182 Environment, influence of, 286 ff.; temperature, 288 ff., 344 ff.; salinity, 306; adaptation to, 319 Enzyme action, 23 ff., 297, 302 Ernst, A., 21 Eternity of life, 34 ff., 360 _Eudendrium_, 260, 261, 269, 277, 278, 326 _Eudorina_, 277 _Euglena_, 264, 269, 272, 277 Euler, H., 21 Evolution, 346 ff.; and mutation, 348 Ewald, W. F., 261 ff., 269, 280, 301 Farmer, J. B., 347 Fermi, 350, 354 Fertilization, heterogeneous, 48 ff., 51, 73 ff.; specificity in, 71 ff.; and oxidation, 117 ff.; and permeability, 119 ff. “Fertilizin,” 84, 87 ff., 93 Fischel, 187 Fischer, 303 ff. Fish, 55 Fitness of environment, 317 Fitzgerald, J. G., 63 Flow of substances and regeneration in _Bryophyllum_, 161 ff. Fluctuating variations, 6, 297 ff., 346 ff. Folin, 22 Food, influence on polymorphism in wasps, 222 ff. Food castration, 224; influence on sexual cycle in rotifers, 224; on metamorphosis in tadpoles, 155 Ford, 63 Forssmann, 63 Frédéricq, 351 Free-martin, cause of sterility, 218-219 Friedenthal, H., 53 ff., 60 Frisch, K., 278, 279 Fröschel, P., 263 Fuchs, H. M., 90 _Fucus_, 123 _Fundulus heteroclitus_, 51, 116, 147, 300, 301, 302, 307 ff., 321 ff., 328 ff., 335, 337, 357 ff. Galileo, 346 Galvanotropism, 11, 270 ff., 319 Gay, F. P., 62 ff. Generation, spontaneous, 14 ff., 34 Genes, 4 ff., 152, 319 Genus and species, chemical basis of, 40 ff. Geppert, 358 Germination in seeds, 35 ff. Giard, 180, 216 ff. Godlewski, E., 48, 75, 78, 120, 126, 169 Godlewski, E., Sr., 18 Goebel, K., 154, 161 Goldfarb, A. J., 326