April 11, 1913] 



SCIENCE 



545 



(d) That the germinal bases of heritable 

 unit characters can be changed or altered 

 in any respect, only with the greatest diffi- 

 culty, if at all. It is, I believe, fair to say 

 that there is at present no critical, unchal- 

 lenged evidence that any alteration can be 

 produced. This matter has recently been 

 discussed in a most able manner by East.' 

 The weight of evidence at present indicates 

 that selection does not act in the manner 

 it was long supposed to, in accordance with 

 Darwin's interpretation. It appears that 

 selection, however stringent or long con- 

 tinued, is powerless to alter in any way the 

 original potentialities of the germinal basis 

 of a unit character. Selection appears to 

 be essentially a process of sorting out from 

 a mixture of heritable variations what is 

 already there, and not a germinally creative 

 or germinally additive process. 



So far this discussion has been ap- 

 proached from the standpoint solely of 

 animal breeding. It is perhaps allowable, 

 even before this animal section, to digress 

 for a little and discuss plant breeding. The 

 ultimate objective point of the animal 

 breeder is the same as that of the plant 

 breeder, namely the greatest possible im- 

 provement of animals and plants and their 

 adaptation to the needs of man. The prac- 

 tical method of working towards this goal 

 is, however, somewhat different in the two 

 fields. The animal breeder almost ex- 

 clusively works towards the amelioration of 

 existing fixed and "pure" breeds. Espe- 

 cially among the larger domestic animals 

 such a thing as a 7iew breed is brought for- 

 ward by the breeder only on very rare 

 occasions. Almost all of our existing breeds 

 of horses, cattle, sheep and swine have long 

 histories as "pure breeds," and no new 

 ones are being added now. With smaller 

 animals such as poultry the case is of course 



'American Naturalist, 1912. 



somewhat different. There we have no reg- 

 istered pedigrees and, with some difficulty, 

 new breeds may be launched. 



The plant breeder, on the other hand, 

 makes nearly all of his improvements by the 

 production of new varieties. This he does 

 either by hybridization, actually building 

 up a new type, or by isolation of superior 

 pure-breeding forms from already existing 

 mixtures. He is not hampered by a body 

 of tradition that only the "pure bred" is 

 of any particular value. Almost if not 

 quite every one of the most valuable strains 

 of agricultural plants to-day carries the 

 ' ' bar sinister. ' ' To the animal breeder they 

 would be "grades" or "crosses" however 

 gametically pure and only with the greatest 

 difficulty would ever have gained a chance 

 to show their worth. 



No one would deny that the systems of 

 registry for live-stock and the exploitation 

 of the "pure-bred" have been of great 

 value in the development of the animal in- 

 dustry of the world. They certainly have ; 

 and every day the economic importance of 

 the system becomes greater, for obvious 

 reasons. All systems of pedigree registra- 

 tion operate economically precisely like a 

 monopoly. As such a plan of developing 

 the live-stock industry of a country grows, 

 the more difficult does it become for a. new 

 creation of the breeder to get a foothold. 

 If it is new, it is by definition not "pure- 

 bred," because if it were "pure-bred" it 

 must belong to one or another of the estab- 

 lished breeds. But anything not "pure- 

 bred" has no recognized standing, or 

 market value. Without regard to the mer- 

 its of the individual the mere fact of pedi- 

 gree registration adds a definite and not 

 inconsiderable amount to the monetary 

 value of an animal. In last analysis this 

 fact is to-day one of the strongest argu- 

 ments which can be made to the farmer in 

 favor of keeping "pure-bred" animals. 



