14 



In seeking support for his theory of "an origin of species by sudden 

 ' mutations ' " and in searching for evidence to show the " high practical value 

 of elementary species which may be isolated by a single choice", De Vries 

 has endeavored to interpret the results obtained at different institutions in the 

 terms of his hypothesis. It was in this way that the Swedish Seed Associa- 

 tion at Svalof, Sweden, was first brought into prominence, especially in 

 America, since in his book " Plant Breeding" (79) published in 1907, De Vries 

 dealt at some length with the work being carried on at that institution. Our 

 thanks are due Dr. De Vries for bringing this work to our attention and for 

 suggesting new and interesting lines of thought and modes of thinking. 

 Unfortunately, however, the principles of plant improvement now actually 

 recognized by the experts at Svalof, not being in full agreement with those 

 described by the above author, a wrong impression regarding the work at that 

 place has been spread abroad. 



After elaborating upon the composite nature of our ordinary cultivated 

 varieties, as demonstrated by the studies of the men in Sweden, De Vries 

 states his point of view clearly and concisely as follows: 



"The range of variability disclosed by these new studies is simply so 

 wide that it affords all the required material for almost all the selections 

 desirable at present, and will no doubt continue to be an inexhaustible source 

 of improvements for a long succession of years. They are founded on the 

 principle of single selections, and the range of application of this method is 

 proven to be so extensive as to make all ideas of repeated or continuous 

 selection simply superfluous. It is even so rich in its productiveness that 

 there is scarcely any room left for other methods of improvement; and 

 especially should all endeavors of winning ameliorated varieties of cereals by 

 means of hybridization simply be left out of consideration, as compared with 

 the immense number of more easily produced novelties which this method 

 offers." (I.e. p. 50). 



The inference here is clear. Our ordinary varieties are composed of a 

 mixture of distinct types. These are so numerous as to render the production 

 of new forms by artificial hybridization quite unnecessary. The problem 

 of the breeder is simply to isolate and propagate the most promising forms 

 and by a process of elimination, finally to locate the best. The discovery of 

 these forms is supposed to be aided by the -fact that certain botanical or 

 morphological characters are indicative of or correlated with industrial 

 qualities, thus : " Whenever a distinct quality is desired, either in order to im- 

 prove a local variety, or to bring it into a form suited for other conditions of 

 soil or climate, or to comply with any other wishes of agricultural practice, it 

 is necessary only to know the botanical marks correlated with the desired 

 qualities. On this basis individual plants may be singled out, and after 

 multiplication through a few years, their progeny will probably respond to 

 the demands made, as soon as the industrial qualities themselves are investi- 

 gated." (I.e. p. 277-8). 



The work at Svalof to-day leaves little support for these conclusions. 

 On the contrary, it clearly indicates that these early opinions were based 

 upon insufficient evidence and incorrect interpretation. As time passed, 



