50 THE AIREDALE 



so? Dog breeding is now more uncertain than 

 roulette, twice as fascinating as the stock mar- 

 ket, as interestingly exciting as auction bridge. 

 Make it a matter of mathematically exact rules 

 working out as invariably and regularly as a ma- 

 chine, and the charm has vanished. 



The three principles of Darwin's idea of how 

 and why evolution acts, are heredity, variation, 

 and selection. The law of heredity says that like 

 will produce like; that two Airedales will have 

 Airedale puppies; two Scotties will have Scot- 

 ties; two Irish terriers will have Irish terriers. 

 The law of variation says that no two dogs, even 

 if they be of the same litter, will ever be exactly 

 alike even in the smallest details. No two St. 

 Bernards were ever alike, nor were the smallest 

 teeth of the two smallest Pomeranians ever iden- 

 tical. There is ample evidence to show that the 

 chemical composition of the muscles, bones, and 

 blood of different animals of the same species are 

 different, and even vary considerably in one 

 individual at different times. The law of selec- 

 tion is the law of the struggle for existence, the 

 survival of the fittest. The three laws together 

 make up the theory of evolution by means of nat- 

 ural selection. 



What man does in breeding is the making and 

 improving of species by artificial selection. He 



