90 PRINCIPLES OF BREEDING. 



parent. He says, ''The female parent's influence upon 

 the sex of offspring in cows, and I have reason to be- 

 lieve in the females of our other domestic animals, is so 

 strong, that it may, I think, be pronounced nearly 

 positive.'' He also says, "I have repeatedly proved 

 that by dividing a herd of thirty cows into three equal 

 parts, I could calculate with confidence upon a large 

 majority of females from one part, of males from an- 

 other, and upon nearly an equal number of males and 

 females from the remainder. I have frequently en- 

 deavored to change the habits by changing the male 

 without success." He relates a case as follows: — 

 '' Two cows brought all female offspring, one fourteen 

 in fifteen years, and the other fifteen in sixteen years, 

 though I annually changed the bull. Both however 

 produced one male each, and that in the same year ; 

 and I confidently expected, when the one produced a 

 male that the other would, as she did." 



M. Giron, after long continued observation and ex- 

 periment, stated with much confidence, that the general 

 law upon this point was, that the sex of progeny would 

 depend on the greater or less relative vigor of the in- 

 dividuals coupled. In many experiments purposely 

 made, he obtained from ewes more males than females 

 by coupling very strong rams with ewes either too 

 young, or too aged, or badly fed, and more females than 



