2G4: CROSS BREDS. 



and a few localities, and the small number of undoubted rules 

 that are really known on the subject need not take long to 

 explain. 



PURE BLOOD. 



G39. — In breeding any valuable and costly animal the first 

 thing to bear in mind is that no animal transmits its own qualities 

 with anything like certainty to its offspring unless it has 

 inherited those qualities from both parents, and both of these 

 parents have also inherited them through many generations, 

 without the intervention of any ancestor of a very different type. 

 The first cross between two pure bred animals of a different 

 type, can generally be depended on to produce an animal of a 

 certain form and character, sharing the qualities of both parents ; 

 but such cross bred animals have no power to transmit their 

 mixed qualiiies with any certainty to their progeny, or to carry 

 on any characteristics they may themselves possess. Even when 

 crossed again with one of the pure bred animals from which it 

 has derived its existence, it may or may not produce something 

 more consistently like that parent. Even when this has been 

 repeated frequently enough to leave by calculation a very small 

 fraction of one of the original crosses in the blood that small 

 portion often exerts an inflnenne upon some far jemoved 

 descendants out of all proportion to anything that could be 

 expected from, let us say, a thirty-second, or sixty-fourth part of 

 that blood. 



640. — Thus we cannot sit down and calculate by any rule of 

 arithmetic, how little impure blood either parent may possess. All 

 that we certainly know is, that if any recent impure blood is 

 there, it may come out in any descendant, and be exhibited to an 

 extent altogether beyond any such calculations. Nor will the 

 slightly cross bred parent have the desired power to transmit with 

 overpowering force his own qualities to his offspring as an 

 animal long bred from one pure race will often do. Thus to 

 breed any pure race with certainty, you must have good pure 

 bred parents on both sides, and to breed even a cross l)red 

 animal with any probability of success one parent must be known 



