Fixation of nitrogen, 152 f. 



Flagellates (flaj'^lats), 179 



FlageUum (MjeVtim), 687, 691 



Flatworms, 692 ; regeneration in, 229 



Fleas and disease, 619, 625 



Flies and disease, 619 



Flora, swamp, 78 ; of prairie, 78 



Flour, enriched, 125 



Flowering plants, reproduction in, 398 ff. ; 



life cycle of, 412 

 Flowers, 11, 12, 31; structure of, 398 ff. ; 

 fertilization in, 404 ff. ; as secondary 

 sexual structures, 408 f. ; interdependence 

 of insect and, 410 

 Fluorine (floo'orin), 102 

 Flying and circulation, 196 

 Food cycle, 560 f. 



Food and Drug Administration, 125 

 Food tube of insect, 16 

 Foods, oxidation of, 83 ; and living proto- 

 plasm, 96 ff. ; need for, 1 14 ff. ; groups of, 

 124 f.; lOO-calorie portions of, 126 f.; 

 transportation of, 164; absorption of, 

 170 f.; protection of, 632; in wartime, 

 632 

 Forest Service, 591 

 Forests, virgin, 153 ; conservation of, 590 ff. ; 



and water, 645 

 Fossils, 52, 450 ff.; "pickled", 452 f.; of 



horse, 453 ; "refrigerated", 454 

 Foxes, inheritance in, 493 ff. 

 Frog, 38, 210, 211; development of, 351; 

 metamorphosis in, 355; reproductive 

 organs of, 379 

 Fronds, 371, 385 

 Fruit, 11, 12, 125 



Fruit flies, 357 ; chromosomes in, 489 ; mu- 

 tations of, 512 f. 

 Fumes as occupational hazard, 636 

 Functional disorders, 629 

 Functions, 16, 18; balanced, 532 f. 

 Fungi (fun'jl), frontispiece, 689 ; disease due 



to, 612 

 Funk, Casimir (1884- ), 107 

 Fusion of cells, 374 ff. 



Gall bladder, 167, 303 ; in bird, 173 

 Gallinae (ga li'ne), 30 

 Gallium (gal'i iim), 103 

 Gametes (gam'Sts), 375 ; two kinds of, 385 f. ; 

 formation of, 389 ; of flower, 404 



Gametophyte, 385 



Ganglia (gang'glio), 276, 278, 279 



Gas gangrene, 237 



Gastric juice, 166 . 



Gastrula (gas'troo Id), 362 



Genes (jenz), 488, 491 



Genetics (jenet'iks), 482; applications of, 



496 ff. 

 Genus (je'nws), 37, 38 

 Geographic distribution, 460 ff. 

 Geotropism, in plants, 258, 260 ; in animals, 



262 

 Germ, 125, 377, 507 f. 

 Germination, 82 



Gestation (jes ta'shwn) period, 423 

 Gibbon, 699 ; brain of, 297 

 Gigantism, 306, 310 

 Gills, 208 



Giraffe, 5; teeth of, 176 

 Girdling trees, 147 



Girls, gain in weight by, 115; bai-al metabo- 

 lism of, 118 ff. 

 Gizzard, 173, 176 

 Glands, 172, 302 ; digestive, 167, 169; types 



of, 170 ; fat, 217 ; ductless, 302 ff. 

 Glass snake, 229 



Glomerule (glom'er ool), 218, 221 

 Glucose, oxidation of, 84 

 Gluten (gloo't^n), 97 

 Glycogen (gll'ko jen), 221 

 Gnu (noo), 7 



Goiter (goi'ter), 306; distribution of, 101 ' 

 Gonads, 305, 307, 314 f., 377 

 GoriUa, 51,699; brain of, 297 

 Government and health, 633 

 Grafting of organs, 362 

 Grafts, types of plant, 369 

 Grasses, of prairie, 78; of dunes, 90; of 



Great Plains, 642 

 Grasshopper, 14 f., 352 

 Great Plains, 642 

 "Green-slime", 25 



Growth, of animals, 17; of plants, 17; of 

 organisms, 19; food for, 114f. ; sub- 

 stances determining, 230, 257 ff. ; light 

 and, 255 f. ; steps in, 343 f. ; conditions 

 of, 344 f. ; limitation on, 345 ; reproduc- 

 tion and, 367 ff. ; period of, of mammals, 

 423 

 Grubs, 353 

 Guano (gwa'no), 150 



710 



