7 i8 



INDEX 



Deviation, average, 427 ; nature of, 

 349, 350 ; not transmissible as such, 

 349; standard, 428-431; standard, 

 meaning of, 432, 433. 



Deviation and probable error illus- 

 trated, 441-443. 



De Vries, experiments of, 114-129; ex- 

 perience in plant breeding, 642 ; ex- 

 periments with chrysanthemum, 119- 

 121; experiments with primrose, 

 121-129; production of new species 

 by mutation, 121-129. 



Differentiation, by cell division, 149, 

 1 50 ; causes of, 343 ; from internal 

 causes, 144 ; mechanism of, 142-154; 

 polarity and promorphology of ovum, 



Digitalis, medicinal qualities of, affected 



by locality, 223. 



Digits, meristic variation in, 53-64. 

 Dimorphism of earwig, Shorthorns, 



Herefords, etc., 20. 

 Disappearance of parts, 306. 

 Disappearing parts, 288. 

 Discontinuity in variation, 19. 

 Disease, transmission of, 368, 384. 

 Diseases due to absence of secretions, 



269. 



Distribution, offspring constitute a, 419. 

 Dodd, William, originator of plum, 



I 33- 

 Dog, acclimatization of, 376; behavior 



of, when deprived of brain, 400, 401 ; 



meristic variation in teeth of, 50 ; 



variation in digits of, 57. 

 Dogs, influence of locality upon, 224 ; 



telegony in, 186. 



Dorfmeister, experiments with butter- 

 flies, 262. 



Double personality, 106. 

 Doubling of parts, as head, 67-69. 

 Dutks, relative weight of bones of tame 



and wild, 95. 



Dugong, variation in digits of, 57. 

 Dwarfs, reasons for, 27. 

 Dyads, 166. 



Earthworm, meristic variation in genera- 

 tive opening of, 44. 



Earthworms, regeneration in, 317-320. 



Earwig, dimorphism of, 20. 



Eggs, regeneration in, 324, 325. 



Ehrlich, experiments with mice, 309. 



Eimer, on adaptation, 206-208 ; on the- 

 ory of orthogenesis, 204-208. 



Electricity, acclimatization to, 314. 



Embryos, regeneration in, 324, 325. 



Endosperm, fertilization of, 183, 184. 



Environment, always selective, 351 ; 

 bearing of, on instability of living 

 matter, 290-293, 302-316; cause of 

 evolution of the horse, 302304 ; 

 direct action of, 307; food, 225-230; 

 general effect of, upon development, 

 221-225 ; how influences type of race, 

 290-293 ; influence of, upon cleavage, 

 340 ; influence of, upon partheno- 

 genesis, 178 ; influence of, upon varia- 

 bility, 220-293. 



Epilepsy, transmission of, 367. 



Evidence that is not evidence, 353. 



Evolution, knowledge of, needed in 

 breeding, 5; not confined to mor- 

 phology, 76; Weismann's theory of, 

 152. 



Ewart, experiments in telegony, 186. 



Exercise, effect of, upon functional 

 activity, 95, 96. 



Exophthalmia, transmission of, 367. 



External influences as causes of varia- 

 bility, 220-293. 



Extra wing, 43. 



Eye, effect of light upon, 243. 



Eyes, degeneration of, in cave species, 

 411, 412 ; supernumerary, 51. 



Fads of the breeder, 594. 



Fan-top trees, 112. 



Fashion in animal breeding, 658, 659. 



Fattening, successful in darkness, 246. 



Fear, not present at birth, 403. 



Female, influence upon, by previous 

 mating, 185-189; maturation and re- 

 duction in, 165-169. 



Females, disposal of surplus, 672. 



Fere, experiments of, on chicks, 259. 



Fertility, characters correlated with, 

 197 ; effect of food upon, 226 ; effect 

 of, upon type, 198, 199; effect of, 

 upon type and variability, 449-451 ; 

 importance of, 199, 584, 589; less 

 with extremes of a race than with the 

 means, 491 ; often opposed by selec- 

 tion, 583; relative, 196-200. 



Fertilization, by the polar body, 179, 

 1 80; connection of, with mutation, 

 1 80 ; of endosperm, 183, 184 ; manner 

 of, 161 ; significance of, 170 ; influence 

 of, upon sex, 632, 633. 



Fish, upstream movements, 235. 



Fisher, studies in fistulas, 45. 



Flagellata, acclimatization to high tem- 

 peratures, 379-381. 



Flammarion, experiments with light, 

 245, 246. 



Flatfishes, 415. 



