INDEX 



527 



399 ff., 408 ff., 417 ff. ; and mosqui- 

 toes, 408 ff. ; and science, 507 ff. ; 

 and the soil, 65 ff. 



Soil, 30 ; and bacteria, 396 ; biology 

 of, 66 ; chemical changes in, 66 ; 

 conservation of, 68, 380 ; erosion, 

 47, 380 ; exhaustion of, 66 ; and for- 

 ests, 380-381; increase of, 67-68; 

 intensive cultivation of, 67 ; relation 

 to sprouting, 29 ; as source of organic 

 bodies, 65 



Sound, sensation of, 238 



Spencer, Herbert, 472 



Sperm cell, 299, 327, 459 



Spermatophytes, 481 



Spermatozoa, 299, 329 



Spillman, Dr. \V. J., 450 



Spineless cactus, 453 



Spiracles, 145 



Spirogyra, 76, 266; conjugation in, 296 



Sponges, 430, 431 ; and bacteria, 396 



Spores, 291, 293, 296, 321, 324, 331, 

 332 ; in animals, 294 ; of fern, 294 ; 

 of moss, 293 ; swimming, 295 



Sporophyte, 322, 323, 325 



Sport (mutation), 460, 462, 473 



Sporulation, 326, 404 



Spraying, 423 



Sprouting of seeds, 25 ff., 29 



Stamens, 478 



Standardizing work conditions, 216 



Starch, 51 ; digestion of, 94, 100-101 ; 

 energy in, 75 ; origin of, 54 



Statistics, vital, 395 



Statolith, 241, 242 



Stem, 32, 174 ff., 269 ff., 300, 477 



Stickleback, 332 



Stigma, 301, 303, 304 ff., 31 1, 313 



Stimulants, 119, 131 ff., 253 ff. (see 

 also Alcohol) 



Stimulation, of glands, no, 112, 116, 

 217; of intestines, 119; from meat, 

 106; of muscles, 217; and sensa- 

 tion, 228 



Sting of bee, 373 



Stomach, 82, 83 ; glands of, 84 



Stomate, 70, 71, 88, 144, 261 



Stone Age, 500 



Struggle, competitive, 343 ; for exis- 

 tence, 474 



Suffocation, 169 



Sugar (see Carbohydrates) 



Sun, relation of, to life, 55, 75 



Superstition, 505 



Suprarenals, 188 



Surface, of cell in relation to growth, 

 265 ; reduction of, as protection, 359 

 Surinam Ameiva, 270 

 Survival of the fittest, 472, 474 

 Susceptibility, 198. See also Immunity 

 Swallowing, 82, 100 



Tannin, 202, 255 



Tanning by light, 352 



Tapeworm, 342, 369, 411 



Tap-roots, 45 



Taste, organs of, 226; in selection of 

 food, 1 10-1 1 1 



Tea, 74, 254 



Teeth, 81, 105, ii9ff., 502 



Temperature, and breathing, 1 56 ; and 

 development, 286; and life, 337 

 (see also Heat) ; color changes re- 

 lated to, 353, 362 ; regulation of, in 

 body, 187; relation of, to sprouting, 

 27 



Test, cytolysin, 197 ; precipitin, 197 



Texas fever, 451 



Thallophytes, 480 



Thymus, 189, 285 



Thyroid, 188, 289 ; influence on devel- 

 opment, 285 



Tick, 451 



Tigerstedt on daily food require- 

 ments, 101 



Timber supply, 382, 383 



Tired feeling, 118 



Tissues, 24, 267, 276, 477 



Toads, 329 ; and young, 334 



Tobacco and bacteria, 347 



Tobacco industry, 74, 167 



Tobacco smoke, 162 ff. 



Tonus, 132 



Tools and weapons, 499 



Touch, organs of, 226, 228 



Tourniquet, 191 



Towels, public, 395 



Tower, Professor W. L., 462. See also 

 Frontispiece 



Trachea in man, 148 



Tracheae in insects, 145 



Transformation (metamorphosis), 280 



Transmission, of communicable dis- 

 eases, 317; of modifications, 460 



Transparency, 352 



Transpiration, 71, 72, 178 



Transportation, within organism, 44, 

 79, 174 ff., 179 ff., 185 ff. 



Tree hoppers, 354 



Trees, products of, 377. See also Forest 



