OLD TYPES AND NEW 201 



breed together from the flock or herd those animals 

 which appear most desirable. This has been the 

 method from the beginning and there is a reason for 

 the considerable degree of success that has followed 

 this obvious mode of procedure. The method, however ,i 

 has its limitations because it is entirely phenotypic andS 

 the breeder is sure to find with Dryden that "all as I 

 they say that glitters is not gold." 



Two methods of mass selection, as applied to plants, 

 may be mentioned that differ in the extent to which 

 the environment is recognized as a contributing factor. 



a. The Method of Hallet 



The English wheat-grower Hallet formulated this 

 method in 1869 and it has been in common use for a 

 long time. It consists in placing the organisms to be 

 bred in the very best possible environment and then 

 choosing those individuals making the best showing 

 as the stock from which to breed further, a procedure 

 based upon the deep-seated belief that acquired char- 

 acters are inherited. 



For example, in a field of wheat, plants near the 

 edge of the field which, from lack of crowding or by 

 reason of proximity to an extra local supply of fer- 

 tilizer or any other favorable environmental factor, 

 make a more vigorous growth than their neighbors, 

 are selected in the hope that the gains made by them 

 will be maintained in their offspring. 



We have seen that it is very questionable whether 

 acquired characters due to environmental conditions 



