INDEX 



567 



Vessels, blood, laboratory study of, 151 



Vestigial evidence, of evolution, traces or 

 rudiments of organs in higher animals, 

 387 



Villemin, J. A., experimental research in 

 tuberculosis, 437-438 



Villi, described, 136, 137 



Vinci, Leonardo da, scientific work of, 

 163-164 



Virus, filterable, 393 ; of smallpox, 423- 

 424 



Vitamins, diseases caused by deficiency 

 of, 97-99; names of, 96-99, 101; 

 list of foods containing, 101 ; present- 

 day knowledge of, 99-100, 102-104; 

 sources of, 101 



Vocations, relation of intelligence to, 230- 

 231 



Voice-box, 178 



Von Behring, discovery of diphtheria 

 antitoxin, 451-452 



Von Haeckel, on recapitulation, 388-389 



Von Leeuwenhoek, improved micro- 

 scope, 19-20 ; contribution to contro- 

 versy on origin of species, 240-241 



Von Mohl, Hugo, description of cell by, 

 28 



Vries, Hugo de. See de Vries 



Wasp, care of their young, 297-298 

 Water, need of drinking, 167-168 

 Waugh, C. W., intelligence test to motor- 

 men, 231 



Weismann, portrait of, 335; theory of 



germ plasm, 335-336 

 Wheat, Little Club, 350 

 Whooping cough, after-effects, 478; 



method of spread, 478 

 Widal test, in typhoid fever, 467 

 Wilson, E. B., on heredity, 55 

 Windpipe, 122 

 Woodruff, L. L., experiments with Para- 



mecia, 50 

 Woods, study of royal families by, 357- 



358 



Woody fibers, of plants, use of, 71 

 Worry, causes of, 234-235 ; effect of, 



233-234 

 Wounds, disease through, 497 



Xerophthalmia, cause of, 99 ; treatment 



for, 98, 99 

 Xylem, conductors of water, 69 



Yeast cells, formation of spores in, 250 ; 

 laboratory study of budding in, 248- 

 249 



Yellow fever, 486-492; cause of, 492; 

 commission, 487 ; history of control, 

 487-491; history of, 486-487; later 

 investigations, 492 ; prevalence of, 

 486-487 



Young, protection of, 292-304 



Zygopore, defined, 264-265 ; 266 

 Zygote, defined, 264, 268 





