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TiiK loi'RNAL oi' 1 lI•:Kl•:l)I'^^• 



existed among breeders, so that from 

 hoar\' antiquity to our own days it has 

 always been recognized that one should 

 attempt inbreeding only with the very 

 best stock. Hermann von Nathusius 

 has publich' cx]jrcssed himself in a 

 masterly manner "On Inbreeding or 

 Pairing in Close Relationship."^ As a 

 reaction against much of the one-sided 

 pedigree talk, his declarations had their 

 place as an expression of the period, 

 just as Hermann von Nathusius himself 

 was a child of the period. Today he 

 would express himself very differently 

 on many points could he familiarize 

 himself with the evidence as to the 

 dangerous possibilites of inbreeding 

 which has been acquired by many of 

 the younger experimenters; but he is, 

 unfortunately, no longer with us. All 

 the more must it b:^ recognized how 

 objectively he expressed himself in his 

 clear, simple and logical way, on the 

 main point of our thesis, the evil results 

 of inbreeding. As the Thoroughbred 

 advocates dared to assume without 

 qualification the position that aversion 

 to consanguineous mating was not 

 founded on natural considerations, but 

 derived from moral ones and bolstered 

 up by a false deduction from the evil 

 effects of pairing diseased and blemished 

 animals — then it was high time to state 

 the facts in the case, in the form of 

 general principles. For criticising these 

 extremists and for jjointing out the 

 actual status of the question, Hermann 

 von Nathusius is highly to be com- 

 mended. But we of today must take 

 with a grain of salt the ideas that he 

 put in the form of five pro]DOsitions, to 

 end his discussion of the case : 



1. The mating of closely related animals 

 can result in good progeny; some of the best 

 improved breeds have been built up by that 

 method. 



2. Up to date no indisputable example has 

 been given of close family-ljreeding carried on 

 among animals for even 30 years. 



3. Among many of the most fortunate and 

 exemplary breeds, in-and-in breeding has 

 resulted in deviations from the standard. 



4. (Consanguineous breeding alone, there- 



fore, can not be laid down as an adequate 

 method of breeding. 



5. On the other hand, it would be equally 

 undesirable to abandon it bodily. 



Had Hermann von Nathusius known 

 the studies going on as to the origin of 

 ])rominent breeds and herds, he would 

 have qualified his first statement to 

 say that not only some, but most, of the 

 best breeds of improved live stock 

 resulted from line-breeding. But in- 

 deed, he has exi)ressed this idea more 

 strongly elsewhere. And his last two 

 propositions he would undoubtedly 

 change, to the disadvantage of close 

 interbreeding. For today we have 

 learned through the studies of von 

 Lehndorf, von Octtingen, de Chai^eau- 

 rougc, Rau and younger writers, how 

 im]jortant it is that a herd should have 

 a wideh'-spreading pedigree. But I will 

 not place this side of the question in the 

 foreground just at this time. 



Pusch, too, who was unhappily taken 

 from us so prematurely, cndea\'ored to 

 show the dangers of inbreeding ex])eri- 

 mentally. More and more I am con- 

 vinced that all trustworthy and pro])crly 

 controlled exijcrimcnts in this direction 

 lead us to the same conclusion: Con- 

 tinued inbreeding always must result in 

 weakened constitution, through its own 

 influence. The more we realize today 

 that high transmissible ])erfomiance 

 seems to be bound to individual animals, 

 and the more we endeavor to make use 

 of the blood of these individuals through 

 inbreeding, so much the more must we 

 anxiously guard against deterioration 

 of strength and shape. Othenvise we 

 shall fall into the error made by the 

 early enthusiasts for ]jedigree breeding, 

 who by taking an unduly narrow \-iew 

 spoiled an idea which in and by itself 

 was sound. Knowledge and experience 

 will guide our great breeders in the 

 right wa\'. If, howe\'er, the idea that 

 inbreeding is never hannful begins little 

 by little, and in ever wider circles, to 

 s])read, then the evils which it involves 

 must once more be adequatel\' pointed 

 out. 



'Kleine Schriflen und Fragmente iiber Viehzuclit, Berlin, l.S.SO. 



