310 



INDEX 



Transmission of acquired charac- 

 ters, 157. 



Transplanting sexual glands, 187. 

 Triplet calves, 108. 

 Trowbridge, P. F., 258, 268. 

 Twins, 101. 



Union of egg and sperm, 36. 

 Unit characters, 141. 

 Use and disuse as causes of modi- 

 fications, 212. 

 Uterus, 28. 



Variation, 195. 



among cows, 203. 



causes, 210. 



continuous and discontinuous, 

 150, 151. 



examples of, 200. 



functional, 199. 



germinal, 214. 



infertility of animals, 200. 



meristic, 198. 



morphological, 196. 



physiological, 197. 



use and disuse, 212. 

 Verworn, 1. 



Vilmorin's pure line wheat-breeding, 



292. 



Virchow, 2. 



Viviparous animals, 18. 

 Von Guiata, 231. 

 Von Siebold, 192. 



Waters, 257. 



Weismann, 34, 38, 39, 167, 207, 

 210. 



and Von Guiata's in-breeding 

 experiments, 231. 



theory of reduction, 38. 

 Wentworth, 81, 101, 107. 

 Wheat-breeding, 147, 292. 

 Wheat ration, 263. 



effect on foetus, 263. 



effect of milk secretion, 267. 

 Wilsdorf, 230. 

 Wilson, 8, 33, 36, 38. 

 Wool production, improvement in, 



282. 

 Wright, 74, 246. 



Xenia, 176, 177. 

 Zebra hybrids, 168 



Printed in the United States of America. 



