NILSSON'S DISCOVERY 65 



plants in an arbitrarily chosen direction, was manifestly con- 

 tradicted by nature. The plant develops itself after its own 

 capacity, but does not suffer itself to be forced into other 

 ways. 



The principle of slow and gradual amelioration by so- 

 called methodical selection was thereby condemned. The 

 squarehead wheat showed itself to be as little amenable to 

 improvement as the barley. Even the oats could not be im- 

 proved. The new varieties which were occasionally ac- 

 quired by the process might as well be considered as accidents. 

 Among them was the Princess barley, which had been derived 

 from the introduced Prentice barley, and which gained a 

 high reputation and extensive distribution. In the same 

 way, the Plumage barley yielded some valuable novelties. 

 There was no reliability in the method, nor could it be dis- 

 covered why a result might be obtained in some cases, and 

 in others not. It was clear that the solution of the great 

 problem was to be sought in quite another way. 



In the next chapter I propose to deal with the further 

 experiments of the station at Svalof, which led to the dis- 

 covery of the principle that the elementary species are the 

 true material for selection, and that they are numerous and 

 varied enough to satisfy all the present demands of practice. 

 In order to make this description independent of all dis- 

 cussions of the older principle, I will once more point out 

 the essential differences between the German method and 

 the work of the previous English breeders, as described in the 

 former chapter. In doing so we have to exclude the views 

 of Hallett, who partly participated in the ideas of his coun- 

 trymen and partly held the same opinion as the Germans. 

 The contrast now assumes this aspect: Improvement may 

 be obtained by selecting single excellent individuals, and 

 experience teaches that they will yield a constant and uniform 

 progeny. This is the old English principle, by means of 



