390 ELEMENTS OF GENERAL SCIENCE 



animals so as to produce the best results. If he wishes to 

 produce an animal that will furnish beef in large quantities, 

 he selects and grows the variety which most nearly resembles 

 his ideal. He then tries to create the most favorable envi- 

 ronment by careful feeding, pasturing, and housing, and by 



FIG. Ibl. Diversity of form produced by selection and breeding 



Five varieties of chrysanthemum. All chrysanthemums have descended from 

 a common ancestor similar to the small upper left-hand specimen 



warding off disease. In the same way sheep, swine, driving- 

 horses, corn, wheat, coffee, carnations, and roses are selected 

 and grown under artificial conditions, and results are pro- 

 duced which are often very unlike those found in undisturbed 

 nature (fig. 181). 



402. Progressive results of artificial selection. The Illinois 

 Agricultural Experiment Station has performed some impor- 

 tant experiments to determine the possibilities of changing 

 the food values in different kinds of corn. The accompanying 



