INDEX 



519 



Drugs, action on protoplasm, 132 ; 

 habit-forming, 132, 137, 139, 255; 

 regulations concerning, 257 



Dubois, Professor Eugene, 494 



Dust, and breathing, 155; in indus- 

 try, 159-161 ; and occupations, 158; 

 as source of infection, 126, 158, 

 173, 192 



Dusting, 162 



Ear, 240 ; in man, 502 



Earthworm, regeneration in, 268 ; 

 respiration in, 146 



Eating, habits of, 89, 114 ff . ; and 

 mental states, 114; and muscular 

 work, 116; pleasures of, 113 



Echinodermata, 347, 484 



Economics, and alcohol, 133, 139, 

 253 ff. ; of bacteria, 388, 394 ff. ; 

 and biology, 4, 439 ff., 449, 450 ff. ; 

 of birds, 425 ff . ; of fatigue, 211, 

 213 ff. ; of food, 122 ff., 128, 388; 

 of forests, 377 ff. ; of heredity, 449, 

 450 ff. ; of insects, 311-313, 398 ff., 

 404 ff., 413 ff., 417 ff.; of photo- 

 synthesis, 74, 75; of roots, 46 ff . ; 

 of science, 124, 129, 474, 505-506, 

 512 ff.; of soil, 65 ff., 380, 381; 

 of stems, 176, 202, 377, 453; of 

 tobacco, 167 ff. 



Efferent nerves, 219, 221, 222, 498 



Efficiency, biology and, 4 ; fatigue 

 and, 211, 216; habits and, 251; 

 health and, 124, 128, 172 ; smoking 

 and, 1 66; temperature and, 156; 

 ventilation and, 156 



Egg, of birds, 330 ; of fishes, 327 ; of 

 frog, 275; of insects, 279, 281; of 

 mammals, 330 ; origin of, 457 ff. ; 

 of plants, 299, 304, 320 ff. 



Egg cell, 299 



Electric shock, 170, 373 



Elements, chemical, 9 



Elimination of refuse, 88, 1 18-1 19, 261 



Embryo, development of, 35, 274 ff. ; 

 in seed, 32, 276 



Embryo sac, 302, 324, 478 



Endosperm, 39 



Energesis, 143, 149, 285; and excre- 

 tion, 262 ; oxygen in, 143 ; and res- 

 piration, 261 



Energy, 7; chemical, 7, n; conser- 

 vation of, 10 ; daily consumption 

 by body, 93, 100 ; sources of, 1 1 ; 

 transformation of, 13,70; units of, 91 



Environment, 26 ; and development, 

 285 ff. ; and health, 214; life and, 

 337 ; man's mastery of, 502 ff. 



Enzyme, 78, 79, 396, 397. See also 

 Ferments 



Epicotyl, 33, 358 



Epidemics, prevention of, 122, 125 ff., 

 163 ff., 387 ff., 394 ff., 399 ff., 404 ff. 



Epidermis, 23, 43, 70, 345, 348 



Erosion, 380 



Esophagus, 82 



Etiolation (blanching), 73 



Euglena, 229 



Eustachian tubes, 82, 240 



Evolution, 463, 471 ; applications of, 

 473 ff. ; evidence of, 464 ff .; of horse, 

 466; theories of, 471 ff . ; and man, 



494 

 Exchange, in cells, 144, 174; of gas, 



73-74 

 Excretion, 76, 201, 262; in animals, 



203 ; and fatigue, 208 ; hygiene of, 

 .205 

 Exercise, 116, 118; and breathing, 



152; and digestion, 141; and the 



skin, 207 



Exo-skeleton, 346 

 Experience, learning from, 504 

 Experiment, problems solved by, 28, 



37> 73' 93' II0 ' IJ 4, "5' "7> "i, 



125, 129, 130, 132, 133, 134, 135, 



143, 154, 155, 156, 162, 166, 171, 



175, 176, 182, 183, 189, 193, 208, 



209 ff., 222, 239, 245, 268, 270, 272, 



285, 290, 352, 362, 378, 379, 386, 



398, 404, 407, 410, 442, 446, 448, 



452, 455, 462, 473, 49 8 ' 499' 54> 510 

 Experiment stations, agricultural, 417 

 Expiration, 149 

 Extracted recessive, 449 

 Eyelids, 232 

 Eyes, and light, 229 ; compound, 230; 



human, 232, 502 ; hygiene of, 235 ; 



infection of, 237 



Factory regulations for health, 128, 

 156, 158, 162 



Fall of leaf, 374 



Fat, 51, 52; digestion of, 85-86; 

 origin of, 55 



Fatigue, 208 ; and efficiency, 210 ; ex- 

 cretion and, 208 ; and eyestrain, 

 236; and health, 215; and rest, 

 215; and work, 210, 213, 215-216 



Fatigue poisons, 208 



