of insects, 33; of plant origin, |278|; of starfish, 216; reptiles as, 202; roots as, 119; stems as, 118; taking, 181; tube of frog, |243|; values, tables, |276|; waste in kitchen, 287; why we need, 272. Foraminifera, 182. Forestry, 113. Forest destruction, 112, |113|; fires, 112; of North Carolina, |105|; other uses, 109; protecting, 114; regions of United States, |109|. Formaldehyde, 148. Formation of habits, 354. Four o'clock embryo, |103|. Fresh air, |337|. Frog, adaptations for life, 241; and man, digestive tract, |297|; breathing, 242; circulation, 243, 322; development of, 244; diagram of tongue, |242|; food tube, 243; glands, 243; locomotion of, 241; long section, |243|; metamorphosis, |245|; nervous system, 352; sense organs, 242. Fruit, a typical, 55. Fruit of locust, |55|. Fruits and seeds as foods, 119. Fruits, how scattered, 56. Fuel, daily needs, 284. Fuel values of nutrients, 277. Functions, of all animals, 180; of an animal, 48; of bile, 307; of blood, 313; of cerebrum, 353; of colorless corpuscle, |316|; of lymph, 317; of parts of plant, 48; of red corpuscle, 314. Fungi, 130, 176; moldlike, 135; of our homes, 132. Fur-bearing animals, 204. Gall bladder, 306; insects, 208. Gallflies, 43. Ganoids, |186|, 187. Garbage cans, |377|. Garden fruits, 123. Gastric glands, 303; of frog, 243. Gastric juice, 303. Gastrula, 177, |178|. Genus, 175. Geranium, |45|. German forest, |114|. Germ cells, 251. Germination, of bean, 63; of pollen, |54|. Gills of fish, 234; rakers, 172, 234. Glands, 297, 298, 299; gastric, 303; lymph, 324; of frog, 243; salivary, 299. Glomerulus, |341|. Glottis of frog, 243. Glycogen, 307. Gonorrhea, 156. Grafting, |256|. Grains, 122. Grape sugar, test for, |68|. Gravity, influence on root, 72. Green plants, economic value, 117; give off oxygen, 95; harmful, 127; make starch, 90, |92|. Groups of plants, 174. Guano, 82. Guard cells, 88. Gullet, 297, 300, 301, 302, |303|; of frog, 243. Gymnosperms, 176. Gypsy moth, 215.