PRINCIPLES OF BREEDING. 91 



of females. The myriads of spermatozoa discharged in a single 

 act, amply suffice to render the ovum or ova prolific, provided 

 there is no obstruction to their entering the womb and being 

 there retained. At the same time, during great sexual excite- 

 ment, such obstruction is at times met, or the semen is discharged 

 after having entered the womb, and a second connection when 

 the excitement is less intense will prove more successful. But 

 as some females will take the male after impregnation, and as 

 connection in these circumstances often causes abortion, the 

 female should not as a rule be presented to the male more than 

 twenty-four hours after having been first served. 



Ergot, smut, weakened constitution, digestive and urinary dis- 

 orders, resulting from improper feeding of breeding animals, 

 fright, mechanical injury and other causes of abortion, need 

 only be mentioned here as additional causes of sterility. 



FUNDAMENTAL PRINCIPLE OF BREEDING. 



To turn from the consideration of the mere production of 

 animals to the production of valuable breeds, we find that the 

 foundation of all success lies in the common aphorism like pro- 

 duces like. As the acorn develops into the oak, and the wheat 

 into the wheat plant, as the horse, ox, ass, sheep and pig repro- 

 duce their respective kinds, so are the corporeal, constitutional 

 and mental qualities of particular animals reproduced in their 

 progeny. The rule holds alike as regards good qualities and 

 defects — the bone and sinew, the fire and vigor of the race 

 horse ; the muscular development and energy of the trotter ; 

 the weight, strength and activity of the Clydesdale ; the placid 

 eye, loose-build, heavy hind parts and large vascular system of 

 the Ayrshire ; the rounded form, early maturity and fattening 

 quality of the Shorthorn ; the sweet, juicy mutton of the high- 

 land breeds of sheep ; the fine wool of the Southdown, or 

 merino, or the early maturity and fattening qualities of the 

 Leicester. 



Perhaps no better example of the hereditary transmission of 

 valuable qualities can be found than in the English thorough- 

 bred race-horse and Shorthorn. The Duke of Newcastle and 

 Mr. Fenwick are reported to have said in Cromwell's time, that 

 " the meanest hack from Tangiers would produce a finer prog- 

 eny than could be expected from the best sire of the native 



