INDEX 



447 



Skeleton, of man, 326 ; 



structure of, 325 ; 



uses of, 325. 

 Skeleton building in Protozoa, 



198. 

 Skin, hygiene of, 393 ; 



structure of, 321. 

 Skull, of dog, 313 ; 



of man, 328 ; 



of porcupine, 314. 

 Sleep, and health, 421 ; 



necessity of, 405. 

 Smell, organs of, 407. 

 Snail, forest, 270. 

 Snake, garter, 294. 

 Snakes, value of, 295 ; 



poisonous, 296. 

 Soil, composition of, 21, 91 ; 



organic matter in, 92 ; 



water in, 91, 92; 



weathering of, 91. 

 Soil exhaustion, prevention of, 95. 

 Solution, Fehling's, 70; 



iodine, 66 ; 



nutrient, 93. 

 Sound, character of, 409. 

 Sparrow, English, 307 ; 



white-throated, 309. 

 Species, defined, 157. 

 Spermatophytes, defined, 156, 157. 

 Sperm cell, 36, 199, 200, 208. 

 Spiders, 245. 



Spinnerets of spiders, 245. 

 Spiracles, 235. 

 Spirogyra, 147. 

 Sponge, structure of, 201. 

 Sponges, 207. 

 Sporangium, 149, 1.54. 

 Spores, 149. 

 Sporophyte, a parasite, 153 ; 



in fern, 155 ; 



in moss, 162. 

 Squid, 270. 

 Stamens, 34, 35. 

 Starch, in bean, 66; 



non-osmosis of, 106 ; 



to grape sugar, 71 ; 



test for, 66. 

 Starch grains, 66. 

 Starch making, and milling, 123 ; 



Starch making, by green plants, 121 ; 



chemistry of, 124 ; 



light and air in, 122 ; 



rapidity of, 125. 

 Starfish, 272. 

 Stem, dicotyledonous, 101, 103 ; 



modified. 111 ; 



movement of fluid in, 105, 107 ; 



monocotyledonous, 108 ; 



structure and work of, 98. 

 Stems, 112, 113. 

 Stigma, .35, 69. 

 Stimulants, 344. 

 Stimuh, response to, in paramoecium, 



191. 

 Stomach, mo\-ement of walls of, 358 ; 



nervous control of, 358 ; 



of man, 353, 357. 

 Stomata, 120, 128. 

 Street cleaning, 432. 

 Streets, condition of, 431. 

 Struggle for existence, 57. 

 Sturgeon, 284. 

 Style, 35. 

 Suffocation, 389. 

 Sugar, consumption of, 109 ; 



osmosis of, 106. 

 Sun, a source of energy, 119. 

 Sundew, 130. 



Sunlight, in starch making, 122. 

 Sweat, 392. 

 Sweat glands, 321. 

 Sweeping, 3S7. 

 Swim bladder, 278. 

 Swimmerets, 222. 

 Symbiosis, 187 ; 



between plants and insects, 40, 

 2.57; 



in crabs, 230 ; 



in lichens, 187 ; 



in nitrogen-fixing bacteria, 94. 

 Systematic botany, 157. 



Tadpoles, of frog, 290. 



Tail of birds, function of, 300. 



Tapeworms, 217. 



Taproot, structure, 87. 



Tarantula, 246. 



Taste, organs of, 406. 



Taste buds, 355, 406. 



