INDEX 



249 



Ventral and dorsal differentiation, 

 18 



Verworn, definition of irritability, 

 50; experiments with amoeba, 48 



Vestigial organs, 229 



Voluntary and involuntary move- 

 ments, 24 



W 



Weigert, hyper- regeneration, 196 



Weismann, heredity, 203; matura- 

 tion significance, 206; old age and 

 death, 69 



Wilson, E. B., 14, 27, 204, 

 207, 212; See Sedgwick. 



Winiwarter, sex chromosomes of 

 man, 224 



Woodruff, so-called immortality of 

 paramecium, 69 



Work done by plants for animals, 



125 

 Wright, opsonin, 193 



X 



Xymase, ferment of yeast, 36 



Y 



Yeast, alcohol and acetic acid forma- 

 tion, 35; culture media, 31; endo- 

 enzymes, 37; fermentation, 34; 

 reproduction, 30; spore formation, 

 31; structure, 29 



Zoogloea, jelly secretion by bacteria, 

 38 



Zoology, subject matter, I 



Zymogen, basic substance of en- 

 zymes, 37 



