GENERAL PRINCIPLES OF BREEDING. 65 



I would not recommend, neither does it fol- 

 low as a legitimate deduction from this general 

 law, that great extremes of size should be cou- 

 pled. In fact, Nature has herself interposed 

 many obstacles to prevent such a course of 

 breeding. 



There is not, as has often been alleged, any 

 iijcreased danger in parturition from the use of 

 sires larger than the dams. It is the dam that 

 determines the size and growth of the foetus, 

 and not the sire. Wrong presentations, faulty 

 construction of some parts of the organs of gen- 

 eration or of the pelvic bones of the female, an 

 emaciated or too plethoric condition of the dam 

 at the time of parturition, an unnatural or de- 

 formed foetus, are the usual causes of difficult 

 parturition, and these conditions are brought 

 about independent of the relative size of sire 

 and dam. 



It goes for nothing to say that improvement 

 in any breed has resulted from the use of males 

 of a smaller breed upon females of a larger. If 

 one desires to bring about improvement in any 

 direction he must select with a view to that 

 quality, independent of other considerations. 

 Were I desirous of improving the butter-pro- 

 ducing quality of the Holstein cow I should 

 use a Jersey bull, notwithstanding the male 

 might be smaller that the female. I would 

 couple large, coarse-wooled ewes with a Merino 



