INDEX 391 



Variation, rate of (mathematical), 344 ; 



in biology, 186 ; 



atavistic, 195 ; direction of, 233; fluctuating, 189; must be co-ordinated, 



231 ; mathematical probability of co-ordination of, 233 ; the material 



for selection, 229 ; origin of, 230 ; selected by the organism, 237 ; cause 



of, a pseudo-problem, 242 ; arise de novo, 244. 

 Variables (mathematical), 343. 

 Varieties, specific, 194. 

 Vegetable life, 265. 

 Vertebrates, 249 ; 



adaptations securing mobility, 275 ; ancestry of, 253 ; morphology of, 



249 ; a dominant group, 259 ; distribution of, 260. 

 Verworn, and mechanism in life, 127. 

 Vesalius, anatomical school of, 121. 



Vital activities, integration of, 128; co-ordination of, 171 

 de Vries and mutations, 191 ; 



fluctuating variations inherited, 220. 

 Vital force, 318. 



Van der Waal's equation, 308. 



Weber's law, 16 ; 



a quasi-mathematical relation, 17. 



Weismann, hypothesis of heredity, 182 ; 



hypothesis of germinal selection, 241 ; hypothesis of development, 132 ; 

 mosaic-theory, 131 ; preformation hypothesis, 133 ; hypothesis of the 

 germ-plasm, continuity of the germ-plasm, 181 ; germinal changes in- 

 conceivable, 224 ; size of biophors, 183 ; origin of life, 339 ; spontaneous 

 generation a logical necessity, 339. 



Weismannism, a series of logical hypotheses, 320 ; physico-chemical 

 analogies, and subsidiary hjpotheses, 223. 



Whales, an unsuccessful line of evolution, 274. 



Whitehead, and mathematical reasoning, 347. 



Wilson, mosaic-theory of development, 139. 



Yerkes, and behaviour of Crustacea, 293. 



Zymogens, 92. 

 Zymoids, 94 



