62 APPLICATION OF PRINCIPLES OF HEREDITY TO BREEDING. 



Three years ago he obtained from Doctor Nilsson, of Svalof , a num- 

 ber of the pedigreed or pure-hne strains of barley grown at that sta- 

 tion. Seed of five or more of these were sent to thirty-eight locahties 

 throughout the country in 1907, representing nearly two hundred 

 tests. In all cases more or less transformation occurred in each of 

 the strains under investigation. Generally speaking, every indi- 

 vidual of a given strain went through identically the same trans- 

 formation in the same locality. The results obtained the second 

 year on some thirty locations indicate that the changes made by 

 these plants are permanent as long as they are grown under the new 

 conditions. 



In several instances it was found that a given strain did not behave 

 alike, part undergoing one modification and part another. A care- 

 ful study of one of these cases revealed the fact that one end of the 

 plot w^as on sandy soil and the other on loam and that all the plants 

 at the same end had suffered the same change. 



Doctor Mann has called my attention to the important fact that 

 these changes suffered by pure lines when taken to a radically differ- 

 ent environment from that to which they had been accustomed 

 seem in no way to be adaptive changes. They are apparently not 

 adjustments to the new conditions, but are changes caused by the 

 new conditions. Apparently, they may be advantageous or dis- 

 advantageous to the plant under its new surroundings. 



It is easily seen that by studying this question with types of plants 

 from which all other kinds of variation have been eliminated, results of 

 fundamental importance may be obtained. The conclusions, which 

 are at least indicated by the very meager data at hand, are that these 

 new-place effects produce similar results on similar individuals, that 

 they are permanent under the changed conditions, and that they 

 are fortuitous in character. It is by no means established, however, 

 that these conclusions are general. This is evidently an important 

 and nearly virgin field for investigation. 



NON-MENDELIAN CHARACTERS. 



The only case known to the writer of anon-Mendelian character which 

 has been clearly made out and for which the method of inheritance has 

 been determined is one recently published by Dr. Erwin Baur, of Berlin, 

 and which relates to the method of inheritance of the white margin 

 of certain leaves.^ The white-margined plants produce only pollen 

 and ovules carrying the white tissue character. But when these 

 plants are crossed with ordinary green plants the new individual 

 thus formed is capable of producing both kinds of tissue. It would 



o Since the above was written the publication of Castle's monograph on inheritance 

 in the rabbit has been made by the Carnegie Institution. Had this publication 

 appeared earlier it would have received extended notice in these pages. 

 165 



