Sugar, 98, 125, 138; and starch in plant, 

 165 ; test for, 183 ; in urine, 221 



Sulfa drugs, 242 



Sulfur in protein, 97 



Sunflower, 255 



Sunlight, and vitamin D, 132 ; and life, 

 138 



Surface, of body, 117 



Susceptibility, 244 



Swamp plants, 204 



Sweating, function of, 195, 217 



Swimmerets, 420 



Swordfish, 32 



Symbiosis (sim bi o'sis), 177, 179 



Symmetry, bilateral, 13, 14 



Synapse (si naps'), 277 



System, digestive, 165 flf. ; of bird, fish, and 

 lobster, 173; endocrine, 304 ff. ; nervous, 

 325 ; reproductive, of frog, 379 



Systemic circuit, 192 



Szent-Gyorgyi (1893- ), 109 



Tadpoles, 357 



Tannins, 216 



Tapeworm, 614, 615, 692 



Tap-roots, 204 



"Tarpit", 452, 455 



Taste, 288, 348 



Taxonomy, 7 



Teeth, of vertebrates, 100; decay of, 

 102; of herbivores, 176; of carnivores, 

 177 



Temperature, for germination, 82, 83 ; regu- 

 lation of, in body, 196 



Tentacles of anemone, 92 



Termite (tur'mit), 177, 179 



Testes, 314, 377 



Tetanus {iet'd niis) , 233, 237 



Thallophytes, 688 f. 



Thiamin (thi'c min), 108, 128, 132 



Thorax, of mammals, 14; of insect, 15; of 

 man, 204 



Thrombin (throm'bin), 187 



"Throwback", 497 



Thymus (thl'm«s) gland, 305, 307, 308 



Thyroid (thi'roid) gland, 100, 101, 305, 306, 

 309, 311 



Thyroxin, 100, 101, 306, 309, 311 



Ticks, 616 f. ; and cattle, 346; and disease, 

 625 



Tide pool, 92, 579 



Tissues, stem, 91, 147,354; stalk, 91; muscu- 

 lar, 116; of leaf, 141; conducting, 146; 

 origin of, 349 f . ; transplanting, 362 



Toad, 38; infancy of, 420, 421 



Tobacco, fungus disease of, 244; mosaic 

 diseases of, 445 



Tocopherol (to kof'er 61), 132 



Tomato, 6 



Tongue, sensitiveness of, 288 



Tonsil, 205 



Tonus (to'nf^s), 232 



Toothed leaves, 43 



Toxicology, 232 



Toxoid (tok'soid), 236 f. 



Trachea (tra'kec), 100, 204 



Tracheae (tra'ke e) of insect, 16 



Transfusions, 197 



Transpiration, 140 f., 148 



Transplanting tissue, 362 



Tree, rings of, 581 



Trench fever, 625 



Trichinella (trik'i nel'o) , 616 



Tropisms (tro'plz'mz), plant, 256 ff. ; animal, 

 260 ff.; chemical, 378 



Trypsin (trip'sin), 188 



Tschermack, Erich, 479 



Tubercles (tu'ber k'lz) of alfalfa, 152 



Tuberculosis, 244 ; death rates from, 609 



Tubers, 253, 395 



Tubular glands, 170 



Turgor and osmosis, 88 f . 



Turtles, 211 



Twins, 359 



Tympanum, 15 



Tyndall, John (1820-1893), 341 



Typhoid, agglutination test for, 241, 242; 

 carriers of, 245 



Typhus, 625 



Underground stem, 12 



Ungulates (iing'gia lats), 172 



Unifying processes, 324 f. 



Urea (ure'c), 202 



Uric acid, 221 



Urine, 195 ; composition of, 218 flf. 



Uterus, 380 



Vaccination, 235 f., 237 

 Vagus (va'gz/s) nerve, 296 

 Values, 660 fif. 

 Valves of heart, 190 



718 



