BREEDING IN LINE. 



185 



embodied result of a number of characteristic 

 tendencies struggling together, some stronger 

 and some weaker. Some of these have only 

 been made strongly predominant by the long 

 and repeated selection of the breeder ; others, 

 on the contrary, regarded by him as defects, 

 have been kept down or made subservient — 

 what he calls "bred out." Still, as subservient 

 tendencies they still exist ; he does not know in 

 what way or in what proportion. But when we 

 introduce a sudden cross from another yard, 

 quite a new set of characteristics are introduced 

 into the struggle for predominance. It is no 

 matter for surprise if some of these combine 

 with those of the home strain in new ways, and 

 that so one or other of the subservient or sup- 

 pressed tendencies may acquire fresh power. 

 For some or all of these reasons, a cross with 

 totally alien blood too often entails more or 

 less reversion to something long left behind 

 and overcome — something, we do not know 

 what ; and so far it has a distinct tendency to 

 undo (for the time) what may be the work of 

 years already done. 



These facts and their reasons must modify 

 very considerably what used to be insisted upon 

 in all the earlier works upon systematic breeding, 

 concerning the necessity for continually intro- 

 ducing " fresh blood " into a strain. Such 

 instructions are never pressed now by authorities 

 who have ever bred any animal whatever with 

 success. On the contrary, it is well known that 

 the introduction of such fresh blood into any 

 strain which has once been brought to high 

 excellence, is a most serious matter. In small 

 yards it may be necessary, from inability in such 

 small space to preserve sufficient independent 

 lines of breeding, which alone can supersede it 

 for any length of time. In large yards, which 

 are able to do this, the necessity should be rare, 

 provided proper care is taken to stamp out 

 diseased or weakly stock. Whenever the neces- 

 sity does arise, be it often or seldom, no pains 

 are too great in the way of inquiry or personal 

 visit to the other yard, or anything that may 

 possibly give information, to ascertain what the 

 purchased bird is likely to breed, or if any 

 known tendencies to particular faults e.xist in 

 the strain. Having done all that is possible in 

 this direction, it is best in general, where feasible, 

 to let the purchase be a hen or pullet. Then, if 

 the experiment be even an utter failure (as on 

 rare occasions it may be), the rest of the yard is 

 not tainted by it, and in the more usual result 

 of partial failure and partial success, the wasters 

 can be discarded without further harm, and the 

 more perfect progeny bred back to the home 

 strain with success. If a cockerel is introduced 



he is better mated with one or two hens most 

 carefully selected, making up the pen if required 

 with others whose eggs will not be confused with 

 theirs. Then his produce will be similarly 

 selected, and " bred back " to the strain by the 

 general method presently explained. In all 

 cases birds from the cross should be selected for 

 further breeding with unusual care, with even 

 most rigorous severity, because the newly intro- 

 duced tendencies have become fresh dangers to 

 be guarded against. 



A yard known to be more or less allied in 

 blood is much less dangerous. Thus, a bird 

 may be bought from some one to whom eggs or 

 stock have been previously sold, or from a yard 

 to which the strain partially or wholly owed its 

 origin some years before. Two breeders, who 

 are well acquainted with each other's yards and 

 sell or exchange birds every now and then, can 

 help each other materially in this way, keeping 

 up enough common blood to remove most of 

 the danger from the mere cross, and so imposing 

 no task beyond that of ordinary selection alone. 

 To this interchange of stock amongst five or six 

 breeders in Bristol, was chiefly due the excel- 

 lence and vigour of the Spanish fowl during so 

 many years. To reap such benefits, however, 

 neither party must strive to reap all of it, deny- 

 ing his brother any. Such foolish jealousy will 

 quite defeat its object, since there must be 

 mutual help, and a real willingness to give it, if 

 any real mutual benefit is to be secured. 



It is most important, however, to understand 

 the manner in which, given only a sufficient 

 amount of room, line or pedigree breeding may 



be carried on without a cross. The 

 Line genuine breeder cannot do without 



Breeding. g^ch line breeding ; while, on the 



other hand, if "in-breeding," which 

 is allied to this, be carried on indiscriminately 

 or to excess, a limit is found in physical weak- 

 ness, deterioration, or infertility. Darwin's 

 researches have made it doubtful whether this 

 is any necessary result of in-breeding in itself. 

 It appears, on the contrary, most probable that 

 the cause lies rather in the fact of both parents 

 having the same constitutional taint where there 

 is any at all ; such taint is therefore intensified, 

 like any other point possessed by both parents 

 alike. Where Nature's own severe selection for 

 greatest strength and vigour is carried out, there 

 are many proofs that much and repeated in- 

 breeding seems to cause no ill-effect. But the 

 breeder cannot kill off in Nature's wholesale 

 way, and must fight the danger by other 

 methods. The essence of that danger lying in 

 two parents possessing the very same elements, 



