188 The Origin of Species by Mutation. 



Good examples of mutations can be found in agri- 

 cultural and horticultural literature. But before I give 

 a selection of them I must point out how clearly the dis- 

 tinction between races and subspecies is appreciated by 

 practical authors. Prof. Kurt von Rumker in his often 

 quoted Introduction to the Breeding of Cereals divides 

 his treatment of methodical selection into two parts. 

 One of them deals with selection w^ith a view to improve- 

 ment, the other with selection with a view to the origin 

 of new forms. ^ The object of the former, he says, is 

 to fix characters already present, to stamp them so to 

 speak, and to intensify desirable qualities. 



New forms, however, arise when the changes "do 

 not consist merely in continuous improvement along one 

 line but in the production of new qualities as lateral off- 

 shoots." Such changes occur now and then in our fields 

 and are known as spontaneous variations. ''Nothing is 

 yet known with certainty about the origin of such spon- 

 taneous variation and still less about the causes of their 

 origin." All that we know is that they are inherited. 



After these quotations from Von Rumker the com- 

 mon phrase "the production of new forms" will sound, 

 to say the least, exaggerated : we should be nearer the 

 mark if we spoke of the search for new forms (and of 

 their subsequent improvement, in the usual sense of the 

 term). 



The awnless form of Beseler^s Anderbecker Oats 

 is a very famous example of a form which was found 

 ready to hand in the fields. 



I propose to give now a series of further examples. 

 In almost all the cases the new sorts have come absolutely 

 true to seed from the very beginning when the possibility 



* P. XIV, and 56 and 83. 



