SUBSTANTIVE VARIATION 31 



The sugar content of beets varies from 4 or 5 per cent to over 

 20 per cent. It is also exceedingly variable in cane. Wheat is 

 richer in protein than is corn, but both are variable, and corn 

 has been bred with a protein content higher than that of wheat. 1 



Plants differ in their ability to withstand frost as do animals to 

 resist disease. A single stalk of corn may remain fresh and green 

 when all its neighbors have been killed. Certain individuals seem 

 immune to particular diseases, and appear to be able to resist 

 infection indefinitely. 



Color in general is based upon definite chemical constituents 

 or upon the character of the surfaces presented for refraction of 

 light. In either case it is a matter of inherent quality and is 

 substantive. 



Importance of substantive variation. The significance of sub- 

 stantive differences depends upon the instance. Speaking gen- 

 erally, these differences are of high value. They are usually, 

 though not invariably, correlated with efficiency, and in such cases 

 they possess a utilitarian interest. 



A dense bone is better than a soft and fibrous one. Every- 

 body prefers a good apple to a poor one ; we have a decided pref- 

 erence for certain aromas ; the juicy, highly flavored steak is 

 better than the dry, tough, and tasteless one. 



Color is a utility character among flowers. We buy them for 

 their color, their form, and their odor. They have no other value, 

 and of these characters their coloring is of the most importance. 



Color, however, is in general the most deceptive of all charac- 

 ters, deceptive because it is striking and because we greatly 

 prefer certain color effects over others, even though not correlated 

 with utility. We carry this preference beyond reason. A red 

 apple will sell for more than one of any other color ; yet vye buy 

 an apple not to look at but to eat ; and no one has shown a cor- 

 relation between color and quality in fruit. 



Horses with white skin are proverbially subject to certain 

 diseases. For this and other reasons color has no little signifi- 

 cance in horses, but among cattle it has practically no meaning 

 whatever ; and yet how decidedly do color markings figure in 



1 The lowest protein content discovered in the breeding experiments at the 

 University of Illinois up to date (1907) is 6.13 per cent, and the highest is 17.79. 



