38 PLANT BREEDING. 



printed pages, the school, the nioderu railway and steamship, and 

 electrical agencies are furnishing an environment in which the mind 

 develops and new ideas are created more rapidly than ever, so the 

 plowed field, the fertilized soil, the isolated position of the cultivated 

 plant, giving it more nourishment, and especially the bringing to- 

 gether and crossing and hybridizing of various forms of plant life, by 

 accident and by the intentional effort of man, furnish conditions under 

 whicli varieties are improved and new characteristics are created. 



While the American genius for inventing machinery was being 

 developed, Indian corn and the American trotting horse were being 

 most wonderfully evolved into higher types. While the Japanese 

 mind has been rising out of the lethargy of ages and becoming a val- 

 uable factor in civilization, the sugar-beet plant has been changed 

 from a .species which had held its characteristics through an epoch of 

 historj^ to a tj^pe profoundly different and of enormous value. As 

 the thought of modern Europe has been centered in America through 

 the migration thither of many of her most progressive people, so Bur- 

 bank in his garden, and in a broader way all of our farmers and 

 experimenters, are centering the blood of all the valuable plants of 

 the world into varieties which shall improve plant life in our country. 

 When we view the development of the mind of the human race 

 from its original state to its present achievement we can not predict 

 a limit to its exi^ansion in the future. Nor when the development of 

 useful plant and animal forms, through their changes from a simple 

 beginning to their present complexity, is observed, can we assume that 

 there is any practical limit to the betterment of our jjlant varieties. 

 So far as the present generation is concerned, there is ample room for 

 useful improvements in all classes of economic plants and animals. 

 Since by breeding the value of some plants, as sugar beets, has been 

 enormously enhanced, it does not seem too much to hope that most of 

 our economic plants can be made 25 per cent more valuable than now. 



DEGREE OF RELATIONSHIP IN CROSSES. 



"In-and-in breeding," "outbreeding," and other expressions relat- 

 ing to the close or distant relationship of parents have been prominent 

 subjects among animal breeders. Charles Darwin's dictum that 

 nature causes benefits to arise from crossing and abhors self-fertiliza- 

 tion has been a foundation stone for the theories of writers and 

 teachers upon animal breeding, though many men are skeptical about 

 the application of this statement to some of the many conditions in 

 animal breeding. Plant breeders have even a greater range of con- 

 ditions as to the degree of relationship between parents, because they 

 deal with the self-fertilized and pai'tially self-fertilized species, as well 

 as with those requiring or allowing of the union of the germs of two 

 parent plants. Possibly Darwin's law would more broadly cover the 

 truth if expressed thus: Nature abhors a radical change whicli would 



