INDEX 



569 



410; of horse, 409; of man, 493; 



results of, 431; theories of, 420 

 Excretmg organs, of animals, 103 



(fig.); of plants, 61 

 Excretion, 67, 103 

 Exhaustion of the soil, 271 

 Existence, struggle for, 423 

 Experience, 538; machinery for 



using, 158 

 External senses, 136 

 Eye, 144; accessory structure of, 



145 (fig.); color of, 507 (fig.); 



iris of, 146; retina of, 145 



Family, 413 



Family groups, 194; resemblance, 

 518, 519 



Fasciation, 207 



Fat, 77, 92; decomposition of, 

 262 



Fauna, 452 



Fi generation, 351 



F2 generation, 351 , 



Feeble-mindedness, 520 



Feelings, 166, 186 



Fermentation, 261; acetic, 264; al- 

 coholic, 262; carbohydrate, 261; 

 enzyms, 263 



Ferns, 330 (fig.) 



Fertility of soil, 109, 271; of 

 superior human stocks, 525 



FertiUzation, among animals, 299 

 (fig.); among plants, 338 



Fertilizers, 271 



Fever, 181 



Fibers, muscle, 126 



Fire, use of by man, 534 



Fission, 26 (fig.), 294 



Fittest, survival of the, 425 



Flagella, 22 (fig.), 28 (fig.), 120 



Flagellate motion, 120 



Flatworms, kidneys of, 104; trans- 

 portation system of, 85 (fig.) 



Flavor, 142 



Fleas and plague, 243 



Flexibility of hand, 534 



Flies, gall, 208; and disease, 237; 

 mimicking wasps, 444 (fig.) 



Floating plants, 485 > 



Flora, 452 



Flotation, organs of, 488 



Flowers and insects, 445 



Flukes, 200 



Fly, gall, 207; vinegar, 365 



Foods, 17, 37, 58, 91; animal, ab- 

 sorption of, 97; aninial, classes 

 of, 96; animal, digestion of, 96; 

 annual production of, 37; an- 

 nual value of, 37; contamina- 

 tion of, 234; for the young 

 plant, 339; plant, 38; plant, 

 digestion of, 66; plant, kinds of, 

 64; plant, storage of, 63; plant, 

 movement of, 65; poisoning of, 

 216; utilization of, 73. 



Food requirements of animals, 110; 

 supply, human, 544 



Food-securing adaptations, 434 



Foraminifera, 487 (fig.) 



Forest, coniferous, 461 (fig.); de- 

 ciduous, 458 (fig.) 



Form, perception of, 144 



Formation of images, 144 



Freezing, effects of, 250 



Fright, 166 



Frontage, water, 83 



Frost resistance, 395 



Functional metabolism, 76, 122; 

 waste in, 81 



Fungi, 210; and disease, 219, 224 



Fungus, potato, 211 



Fusel oils, 263 



Fusion, triple, 339 



Future, man's, 504 



Galactose, 265 



Gall fly, 207 



Galls, 208 (fig.) 



Galton, Francis, 518, 519 



Gametes, 297, 324; purity of, 352 



Gametic ratios, 383 



Gametophyte, 330; female, 336 

 (fig.); male, 332, 338 (fig.) 



Ganglion, 152, 154 (fig.) 



Gas exchange in leaves, 60; natu- 

 ral, 44 



Gases, diffusion of, 98 



Gastric juice, 94 



Gastrula, 302 (fig.) 



General Biology, 5 



Generation, alternation of, 330; 

 spontaneous, 293 



Genes, 353; character expression 

 of, 381; complementary, 386; 

 cumulative, 387; differential, 

 381; in chromosomes, 353; in- 

 hibitory, 387; lethal, 399; hnked, 

 segregation of, 370; mutations of, 



