GENERAL INTEODUCTION. 



THE PRINCIPLES OF BREEDING. 



The uncertainties of stock-breeding are proverbial, 

 and fanciers are seldom surprised when the unexpected 

 happens. We speak of the principles of breeding and 

 of scientific breeders, but it looks often as if there were 

 no principles, and as if in breeding the scientific method 

 is inapplicable. Why of all vocations should the 

 breeder's be the most uncertain ? or .shall the question 

 rather be, why of all men should breeders be the most 

 unreasonable, more than all others desirous to " eat their 

 cake and have it " ? The fundamental reason doubtless 

 is that wherever there is life there is variation in one or 

 more directions. Variation is welcomed by breeders and 

 fanciers up to a certain point, but beyond this it is 

 considered a positive disadvantage. When a desired 

 strain, variety, or breed lias been formed the breeder 

 would like to arrest all further variation. As with a key 

 an electric current is switched off, he would like to 

 arrest further change. But not only has variation to be 

 contended with, there is reversion and the evils that flow 

 from inbreeding'. Even when making a new strain much 

 patient work may be lost through prepotency or sterility 

 unexpectedly supervening where least wanted. 



Can science do anything to make the work of the 

 breeder less uncertain and haphazard ? Can it help in 

 the production of new forms, and stereotype them when 

 once realised, so that they may be reproduced, " repeated " 

 with as much certainty as statues are turned out of a 

 mould ? Science is incapable of either creating or, 

 except to a limited extent, controlling life, but yet it may 

 help the breeder to so influence the vital forces in 

 operation that the desired goal is reached without un- 

 necessary Waste of time or energy. 



To all who give a moment's thought to the subject it 

 will be evident that variation, reversion, inbreeding, and 

 prepotency have to be especially reckoned with. Science, 

 in as far as it throws light on these subjects, will doubt- 



