410 PHILOSOPHY OF ZOOLOGY. 



however, which militate equally against the opinions, that 

 the determination of the sex takes place in the ovum, or in 

 the foetus. Mr KNIGHT, whose experiments on plants 

 have greatly enlarged the bounds of vegetable physiology, 

 has communicated the following observations in reference 

 to the subject under consideration. " In several species 

 of domesticated or cultivated animals (I believe in all,) par- 

 ticular females are found to produce a very large majority, 

 and sometimes all their offspring of the same sex ; and I 

 have proved repeatedly, that, by dividing a herd of thirty 

 cows into three equal parts, I could calculate, with confi- 

 dence, upon a large majority of females from one part, of 

 males from another, and upon nearly an equal number of 

 males and females from the remainder. I frequently en- 

 deavoured to change their habits, by changing the male ; 

 but always without success ; and I have in some instances 

 observed the offspring of one sex, though obtained from 

 different males, to exceed those of the other, in the propor- 

 tion of five or six, and even seven to one. When, on the 

 contrary, I have attended to the numerous offspring of a 

 single bull, or ram, or horse, I have never seen any consi- 

 derable difference in the number of offspring of either 

 sex *." Such observations rather support the conclusions, 

 that the sex of the ovum is determined previous to im- 



* " On the Comparative Influence of Male and Female Parents on their 

 Offspring," Phil. Trans. 1809, p. 397. There are some facts, however, 

 which daily occur in the human species, which .appear to indicate that the 

 influence of the male in determining the sex of the foetus is considerable. 

 The following very singular one is from p. 21. of the appendix to Dr GARTH- 

 SHORE'S paper, on " A remarkable case of numerous births, with observa- 

 tions," Phil. Trans. 1787, p. 344. " Mr KIRWAN, a very respectable philo- 

 sopher, and Fellow of the Royal Society, has often told me, that he had con. 

 versed with a gentleman, who affirmed to him, that he himself was the 

 youngest of forty sons, all produced in succession from three different wives, 



