48 DOMESTICATED ANIMALS AND PLANTS 



every character that enters into the composition of individuals 

 and of races. 



Thus among sweet apples some are sweeter than others within 

 the same variety, and this is true quite independent of color or 

 size. Of all the trotting horses in the world some can go in 2 140, 

 some in 2 : 30, a few in 2 : 20, and a very few in 2 105 or less. 



Of a thousand ears of corn taken at random from the same 

 field and of the same variety, some will be short and others 

 long, while the rest will stand between. This is variability in 

 a single character. It is, moreover, a kind of variability that 

 can be exhaustively studied by exact statistical methods, — a study 

 that is strongly recommended not only for its exactness but for 

 its influence in fixing definite notions of type and that devi- 

 ation from type which is called variability. These methods of 

 study are given in a later chapter, a careful study of which is 

 strongly recommended at this point. 



Historical knowledge of original species needed. In order to 

 devise practical methods of still further improving the domesti- 

 cated races and more completely adapting them to the service 

 of men, we need, first of all, to know everything possible of the 

 character of the original species as they lived in a state of nature, 

 — how they behaved toward one another and how they prospered 

 before man interfered with their affairs. In other words, from the 

 way of the wild we can learn substantial lessons as to methods of 

 improvement, and this we propose to outline in the next chapter. 



Summary. No plant or animal has yet been brought to its highest state 

 of efficiency, though some individuals are vastly superior to others, and vari- 

 ability is universal. Besides this, our needs and our desires are constantly 

 changing, mostly by way of advance. There is need, then, for still further 

 improvement, and the best course to pursue in deciding upon methods is, 

 first of all, to study species in a state of nature, where these species existed 

 in the wild for many generations previous to domestication. 



Exercises. 1. The student should calculate with as much accuracy as 

 possible and report upon the cost of maintaining domestic animals in his 

 own neighborhood, especially as influencing the cost of meat and milk 

 production. 



