Index - 723 



249-53; organs and tissues of, 242-53; root and 

 its functions, 244-46; stem and its functions, 

 246-49: tissues of, 242-44 



Vascular region of stem, 248 



Vascular tissues, true, 242, 244 



Vasopressin, 376, 377, 412 



Vector, 578; disease, 581 



Vegetal pole, 273, 277 



Vegetative method of reproduction, 234 



Veins, 327, 328, 330, 332; hepatic, 332, 333; of 

 human body, 331-32 



Vendrely, C, 520 



Ventral aorta, 330. 331 



Ventral root, 461 



Venules, 329 



Vermiform appendix, 554 



Vertebral column. 280. 458. 666 



Vertebrata, 664, 666, 667; Amphibia, 666, 667, 

 670-71; Aves, 667, 672-73; Chondrichthyes, 

 667, 669; classes of, 668-76; Cyclostomata, 667, 

 668-69; embryonic development in. 277-84; 

 mammals, 67, 673-76; Osteichthyes, 667, 669- 

 70; reptiles. 667, 671-72 



Vessels, 244 



Vestigial organs, evolution and, 554-56 



Villi, 310, 311, 339; chorionic, 391-92 



Vinegar bacteria, 177 



Viruses, 7-11; cell of, 20; growth and reproduc- 

 tion, 8, 11; isolation of, 9; living matter, 11; 

 tobacco mosaic, 8, 9; unit structure, 10-11 



Visceral muscles, 286, 287, 328, 439-40 



Visceral receptors, 426 



Visceral reflexes, 465-67 



Vishniac, W„ 161 



Visual excitation, chemistry of, 423-24 



Vital force, 99 



Vitamin hypothesis, 346 



Vitamins, 104, 137, 170, 346-54, 530; food sub- 

 stance, 127; origin and nature of, 354; prin- 

 ciple, 348-49; in protoplasm, 89; storage of, 

 343 



Vitelline membrane, 274 



Vocal cords, 360 



Volkin, E., 525 



Volvocaceae, 59; sexual reproduction of, 61 



Volvox, 59, 61 



Vorticella, 196 



75; dispersion medium, 71; dissociation of, 73; 

 electrolytes and nonelectrolytes, 73; equilibrium 

 in the cell, 118-21; food substance. 127; hydro- 

 gen and hydroxy! ions, 73; photolysis of, 162; 

 reabsorption of, by kidney, 375-76; in relation 

 to dissociation, 72-73: salts, acids, bases, and 

 respective ions, 74-75; solutions, acid, basic, 

 and neutral, 73-74; solvent properties of, 71- 

 72; thermal properties of, 72; transport mech- 

 anisms, 123 



Water-in-oil emulsion, 93, 94 



Water vascular system. 662, 663 



Watson, j. D.. 135. 521 



Weismann. A., 38 



Weiss, S„ 525 



Went, F„ 261-62 



Wheat rust, 607. 609 



Wheel animals. 641-42, 643 



Whelks, 652, 653 



White corpuscles. 289-90, 321-23 



White fibers. 288 



Wigglesworth, V. B., 414 



Wilkins, M. H. F., 521 



Williams, C. M„ 414 



Wilson, A., 165 



Wood, 244 



Worms, earth (sec Earthworms); filarial, 645; flat, 

 635-41; guinea, 644; ribbon, 641; sand, 647, 

 648, 649; segmented, 647-49; ship, 651; tape, 

 636, 639-41; tongue, 665; tube, 649 



X 



Xanthophyll, 159 



Xerophthalmia, 350 



Xerophytes, 585, 586 



Xylem, 243, 244, 247, 248, 219, 250, 609, 611 



Y 



Yeast, 173, 174; anaerobic metabolism of, 175; 

 cells, 56; economic importance of, 176; multi- 

 plication of, 539; nutrition of, 174-75 



Yellow- fibers, 288-89 



Yolk plug, 281 



Yolk sac, 388, 389 



W 

 Wald, G„ 186,423 

 Wasps, 658, 659 

 Wastes, egestive, 131; metabolic (excretory), 132, 



133: nitrogenous, 138 

 Water, 71-75, 158, 159, 369, 388; as abiotic 



environment, 585-86; chemical activity of, 72- 



Zoology, 14 

 Zooplankton, 589 

 Zoospores, 57 

 Zostera marina, 574 

 Zygospore, 58, 211 



Zygotes, 27, 40, 51, 60, 61, 271; nucleus of, 57, 

 257 



