INDEX 



439 



Roots, absorption through, 220 



anchorage, 222 



definition of, 219 



excretion through. 221 



structure of, 220 

 Rust, 94, 168 



Saliva, 316, 322, 323 

 Salts, 107, 302, 357 

 Sand, 165, 190 



dunes, 165 

 Sanitation, 42 Iff. 

 Saprophyte, 243 

 Saturation of atmosphere. 125 

 Science, definition of, 1 

 Seasons, 152 

 Secretions, in the mouth, 316 



internal, 367, 368 

 Seed dispersal, 238 

 Seeds, formation of, 234 

 Senses, the special, 397ff. 

 Sensitiveness, of animals, 281 



of man, 399 

 Sepal, 233 

 Serums, 415 

 Skeletal system, 370ff. 

 Skin, care of, 365 



structure of, 360 



uses of, 359 

 Smell, 399 

 Snow, 126 



Sodium hydroxide, 106, 108 

 Soil, kinds of, 190, 191, 192 



Dryer's classification of, 192 



origin of, 186 

 Solar plexus, 389 

 Solids, change in volume, 47 



change to liquids, 35, 37 



effect of heat on, 13 



heat given off when liquids 

 become s., 38 



heat necessary to dissolve, 38 



melting points, 39 



molecules in, 8 

 Solutes, 187, 188, 206, 219. 220, 



302, 322 



Spiders, 264, 267 

 Spinal cord, 384, 387 

 Spleen, 369 

 Sponges, 198, 269 

 Sprain, 377 

 Stamen, 234 

 Starch, digestion of, 324 



formation of in plants, 204, 

 301 



test for, 301 

 Steel, 87, 88 

 Stems, functions of, 225 



kinds of, 225 



structure of, 227 

 Sun as a source of heat, 124, 



150 



Sterilize, 245, 247, 308, 428 

 Sternum, 372 

 Stimulants, 328ff. 

 Stomach, 310, 317, 323 

 Stomate, 201, 202, 214, 215 

 Storms, 137ff. 



definition, 141 



kinds of, 142 



Streams, effect on human ac- 

 tivities, 182 



development, 175, 178, 179, 

 181 



erosion, 172 

 Sugar, 301, 324, 326, 369 



test for, 301 

 Sulphur, 77ff. 



dioxide, 94 



Talus, 168 

 Tarsals, 373 



