NATUKB OP PEDIGREE BEEEDING. 47 



other brov/u, the black-haired parent has a tendency to transmit 

 that feature to the offspring, but it is counteracted or modified 

 by the tendency of the other to transmit brown, and by the 

 colour of the hair in ancestors further back. 



Now the kind of breeding which is necessary to form a 

 really valuable strain, consists in throwing the effect of all 

 these tendencies into one selected direction ; or, in other words, 

 causing the tendencies of great-grandparents and grandparents, 

 as well as of the immediate- parents, to combine and unite 

 towards the desired object. Let us go to the pigeon-loft for an 

 illustration. It is by no means uncommon to find a Fantail, 

 through some remains or cross of a strain now nearly extinct, 

 with a crest or peak at the back of the head. Stiictly speaking, 

 this is inherited from some ancestor ; but for present purposes, 

 we may consider it an accidental variation : any way, it 

 occurs only rarely among common FantaUs. If only one such 

 bird be bred from, say a hen, it is probable one or two of her 

 progeny will exhibit the crest, the greater part reverting, or 

 " throwing back," to the usual type in the loft. If a cock can 

 be found — also of the ordinary strain — showing the same 

 peculiarity, the number of progeny exhibiting it will be some- 

 what increased ; but stUl, supposing- the taint or trace in the 

 strain to be very minute, they will probably not be many, and 

 such ^Zam-headed birds as are produced will not show much 

 tendency to produce crests.* But now suppose we can select 

 from this first progeny a pair both crested, and breed them 

 together. We shall now find the tendency vastly increased, 

 so much so that very likely a good half of the next progeny 

 may be crested, and even those which are not will show some 

 marked tendency to produce crested birds. If we breed from 

 this third generation again, still Selecting crested birds, the 



* We ai-e speaking of general average results ; occasionally a bird -will 

 manifest a power of reproducing his or her own characteristics of an extra • 

 ordinary degree, birt this will not affect our explanation. 



