336 PRINCIPLES OF STOCK-BKEEDING. 



are just these : I take for granted that every alternate 

 egg or ovum presented for impregnation is a male. 

 Consequently, if a cow has a bull-calf, the next egg in 

 her rotation must be a female, and, if impregnated 

 when presented, the produce will be a female, etc." 1 



It will be difficult to reconcile the hypothesis 

 presented by Mr. Stuyvesant with the cases in which 

 the sex of the offspring is apparently determined by 

 the male parent, the proportions of the sexes observed 

 in plural births, or with the observed influence of 

 nutrition upon sex in insects, recorded by Mrs. Treat 

 and Mr. Gentry. 



In the last-mentioned cases the sex was not deter- 

 mined until the embryo had reached an advanced 

 stage of development, and the eggs could not, there- 

 fore, have been endowed with sexuality ; and we have 

 no physiological reasons for the belief that the ovum 

 of the higher animals presents an exception, in this 

 respect, to the general law that governs the function 

 of reproduction. 



1 Country Gentleman, 18Y7, p. 415. 





