EFFECTS OF INBREEDING 



A Valuable Instrument, But Fraught With Danger Experiment Shows That if 



Long Continued, Its Effects are of Themselves Evil, Regardless of 



the Strength of Constitution of the Animals Involved.' 



II. KkAK.MIiK, 



Professor in the Landwirtschaftliche Hochschiile of Hohenheim, Germany. 



D 



URING the past few months I 

 hax'C been receiving a con- 

 tinually increasing number of 

 inquiries about the present 

 status of inbreeding. People are now- 

 adays constantly reading and hearing of 

 its absolute harmlcssncss, while until 

 a short time ago it was held up to them 

 as utterly unpcrmissil)le. It seems 

 desirable, then, to review some of the 

 results of experience, and to state my 

 own views as to whether consanguineous 

 breeding really results injuriously. 



The reliable observations made for 

 many years past in every possible 

 branch of breeding and in all kinds of 

 herds, have thoroughly illuminated the 

 question for anyone who is able to 

 follow the truth when he sees it. But I 

 must conclude, from the great number 

 of letters I receive, that men are not 

 able to follow the truth very often. 

 And although the conclusions justified 

 by these breeding cx])criments be 

 known, yet some em]:)hasis should be 

 laid on the other sirle as well. The new 

 and Vjctter knowledge of the great value 

 of pro|ierly-directed inbreeding will 

 surely not cause anyone to go astray. 

 And certainly it is not for a minute my 

 intention to lead anyone astray on this 

 suljject. 



The present age has directed re- 

 searches about consanguineous breed- 

 ing in the right direction. If we are 

 thereby led to indorse in all Ijranchcs of 

 stock-breeding a i)roce(lure so nnuli 

 feared in earlier times, that lies in tlie 

 nature of things. Our delight in the 

 discovery of the high importance of a 



pnncii)k' always leads us too easily to 

 pass ]jy the darker sides, the aspects 

 which should cause us to hesitate; and 

 the serious results following inbreeding 

 are now too lightly regarded in hand- 

 books of stock-breeding. And when 

 isolated breeders go so far as to declare 

 that inbreeding produces no serious 

 consequences whate\-er, then it is again 

 time to recall the innumerable eases 

 recorded from the experience of well- 

 known breeders of the past. In this 

 retrospect, the literature of the various 

 civilized countries in earlier days furn- 

 ishes a picture that can not be misin- 

 terpreted, and I shall therefore attempt 

 to present it here. Such a literar>- 

 review will jjcrhaj^s be able to correct 

 our vicwjjoint while broadening it, now 

 that the English breeders have become 

 such unconditional friends of inbreeding. 



U.VRWIX'S lXVHSTIG.\TIONS. 



Among the linglish writers who have 

 dealt with the subject, Darwin naturalK- 

 comes first to mind. We are too mucli 

 accustomed to think of his work as going 

 wholly backward and dealing only with 

 origins. I want, therefore, at this point 

 to commend most wannly to breeders 

 the jjcrusal of his book on "The \'aria- 

 tion of Animals and Plants under 

 Domestication." What a mass of 

 stimuli to us in our work! What a 

 mighty faculty for observation! What 

 a sur])assing talent for liringing innum- 

 erable details together to make a unified 

 picture! This book should be in the 

 l)ossession of every breeder who wishes 



'Translatii<n of "Ulxr die ungunstiRL-n WirkuiiKcn naluT Inzuclit," in Mittoilung dcr 

 Deutschc's^' Landwirlsdiafts Gesellschafl, 6 and 1.? Si'pU-mli.>r, 1'>I.V 



226 



