94 Elementary Species 



tained from them show that nmnerous types 

 of variability were usually thrown together. 

 What type in each case afforded the material, 

 which the breeder in reality made use of, has 

 only been inquired into in the last few decades. 

 Among those who have opened the way for 

 thorough and more scientific treatment are to 

 be mentioned Rimpau and Von Riimker of Ger- 

 many and W. M. Hays of America. 



Von Riimker is to be considered as the first 

 writer, who sharply distinguished between two 

 phases of methodical breeding-selection. One 

 side he calls the production of new forms, the 

 other the improvement of the breed. He dealt 

 with both methods extensively. New forms are 

 considered as spontaneous variations occurring 

 or originating without human aid. They have 

 only to be selected and isolated, and their 

 progeny at once yields a constant and pure race. 

 This race retains its character as long as it is 

 protected against the admixture of other minor 

 varieties, either by cross-pollination, or by ac- 

 cidental seeds. 



Improvement, on the other hand, is the work 

 of man. New varieties of course can only be 

 isolated if chance offers them; the improve- 

 ment is not incumbent on chance. It does not 

 create really anything new, but develops char- 

 acters, which were already existing. It brings 



