Conduction, in plants, 157-159' 



Conifers, 81-82 



Conjugation, 415-417; bread mold, 416-417, 417; 

 def., 417; of Paramecium, 417; of spirogyra, 415- 

 416, 416 



Connective tissue, 131, 194 



Conservation, forest, 399-402; soil, 403-405; sum- 

 mary of, 406-408 



Contact poisons, 394-395 



Continuity of germ plasm, 455, 488, 489 



Contour planting, 405 



Contractility, 269 



Contrasting characters, 467-468 



Convolutions, 271, 272 



Convulsion, 255 



Cooking, and vitamins, 182 



Coordination, and cerebellum, 273 



Copperhead, 27, 28 



Coral reefs (islands), 60 



Coral snake, 27-28 



Corals, 59-60; organ-pipe, 60 



Cork, 105, 106, 156; of roots, 152; of stems, 

 153 



Corn, 84; and corn borer, 392, 392; chromosome 

 number of, 459; effects of selection of. 495; fat 

 in, 143; flowers of, 440; gene and light. 490; seed, 

 438; smut, 386, 386; stem. 157; water loss in, 

 159 



Corn borer, larvae, 392 



Cornea, of eye, 280, 280 



Corolla, 439 



Cortex, of adrenals, 253; of brain, 272, 274; of 

 human brain, 271, 276; root, 151, 152, 152; stem, 

 15.3-154, 154 



Cortin, of adrenals, 253 



Cosmetics, 242 



Cotton, 88-89; fats in. 143; fruits, 383 



Cotton boll weevil, history of, 389 



Cottonseed oil, 89 



Cotyledons, def., 451; in plant reproduction, 443 



Coughing, and disease spread, 322 



Cousin marriages, 512 



Cover crops, and soil erosion, 405 



Cowpox, and smallpox, 325-326 



Cows, in model farm, 504; muscle cells of, 129 



Crab, 41, 52, 53 



Cranium, def., 15, 271 



Creosote, 385; use of against termites, 49 



Cretinism, 248 



Crocodiles, 29-30 



Cro-Magnon, man, 570-571; art, 571; artist at 

 work, 570 



Crops, cover, 405; rotation of, 405 



Crossbreeding, def., 496 



Cross-pollination, def.. 441 



Crosses, Andalusian fowl. 468; in breeding, 497, 

 499-502; cat, 465; cattle, 499-501, 500; dihybrid, 

 470-472, 472; four o'( lock, 464-467; fruit fly, 470, 

 471; guinea pig, 469, 470; pea, 467-468, 469; rat, 

 469; squash, 469 



Crossing over, def., 477 



Crustaceans, 41, 41, 52-53, 53, 373 



Culex (mosquito), 349; life history of, 352 



Culture, Bronze and Iron Age, 573; def., 565; of 

 early man, 570-571; New Stone Age, 572-573; 

 Old Stone Age, 571-572 



Culturing bacteria, 312-314; medium, 313 



Cutting, def., 449 



Cyclotron, 250 



Cylinders, root, 151-153. 152; stem, 153-157, 154 



Cytoplasm, 106, 107, 111 



Daddy longlegs, 51 



Daisy, 89; Shasta, 502 



Dam, beaver, 264 



Dandelion, 89: parthenogenesis in, 449; seeds, 445 



Darwin, Charles R., 57; theory of evolution of, 556 



Darwin-Wedgwood pedigree, 512 



Datura, and heredity, 481 



"Daughter" cell, in reproduction, 413-414 



Da Vinci, Leonardo, and fossils, 526 



Daydreaming, 368-369 



DDT, and insect control, 395 



Death, by accident, 362; Black, 328; from bubonic 

 plague, 343; causes of. 360. 360; causes of in chil- 

 dren, 362; from diphtheria, 329, 330; infant rate, 

 369-370; from smallpox. 325; from tuberculosis, 

 321; and tobacco, 365-366; from typhoid, 345 



Decay, and cycles, 376; and nitrogen cycle, 377-378; 

 of teeth, 204 



Deer, 169, 421 



Deficiency diseases, def., 178 



Delta, formation of, 523 



Dendrites, 274, 274-275, 277; and nerve impulse, 

 276-277 



Denitrifying bacteria, 377 



Dermis, of skin, 241-242 



De Vries, Hugo, 482; and Darwin, 559; and muta- 

 tions, 482-483; and theory of evolution, 555, 561 



Diabetes, 250-252, 311; use of insulin in, 251 



Diaphragm, human, 228, 229. 321; microscope, 113 



Diarrhea, and allergy, 364 



Diatoms, 74; and food chains, 373 



Dicot (dicotyledon), def.. 83; 8.5-90. 91; seed, 438 



Diet, 167-187; and calories. 170-174; carbohydrates 

 in, 174; experiments, 157, 176, 177; fats in, 174- 

 175: minerals in, 175-176; proteins in, 174; rough- 

 age in. 176; vitamins in, 176—183; water in, 175 



Differctitiation. 131; def., 426; in plants. 443 



Diffusion, 121-124, 122, 188-189: of air in lungs, 

 231: and blood, 208-209; and capillaries, 206-207; 

 in cells. 123; conditions of, 123-124; effect on cells, 

 125; in gases, 122; in liquids, 122; in lungs, 228; 

 and lymph, 221; and molecules, 122-123; in root 

 hairs, 150-151; through membrane, 122-123. 123 



Digestion, 125, 188-205; by bacteria. 312; def., 189- 

 190; tliagram, 197; of fats, 196-197; intermediate 

 products of, 190, 194, 197; in mouth, 192; in 

 plants, 158; products of, 190, 196, 197, 197; of 

 protein, 194-196; in small intestine, 196-197; of 

 starches, 190, 192, 196; in stomach, 193-194 



Digestive enzymes, 190-191 



Digestive glands, 190-191, 191; stimulation of, 199- 

 200 



Digestive juice, 191 



Digestive system, of man, 188-205, 189 



Dihybrid, 471-472; cross, 472; gametes, 471, 472 



Dinosaurs. 526. 537-538, 537; footprints of, 527 



Diphtheria, 316, 328; and active immunity, 329, 

 carriers, 347; death rate, 330; effect of antitoxin 

 on, 329; and passive immunity, 328-329; sus- 

 ceptibility test, 330 



Diploid, def., 460 



Disease, advance in understanding, 338-342; com- 

 municable (see Infections); deficiency, 311; def.. 

 311; 311-371; and drugs, 332; epidemics, 343; and 

 future, 341; germ theory of, 320-321; heredity of. 

 510; infectious, 320; intestinal. 340-341; meta- 

 bolic, 311; and milk supply, 345-347; organic, 311; 

 summary of conquest, 334; venereal, 332-333; 

 virus, 340; water-borne, 344-345 



Disinfectants, 315; and surgery, 331-332 



Dispersal, seed, 444-445, 445 



603 



