28 VARIATION 



The causes involved in this abnormal behavior of the cell in 

 division are exceedingly obscure. They are certainly sometimes 

 connected with food and care in early life, and no doubt they 

 are often constitutional. Every stockman knows about the 

 stunted pig, calf, or colt, and that it sometimes, but rarely, 

 recovers; that is to say, cell division once checked does not easily 

 return to the normal rate. The trait, however, easily becomes 

 constitutional and hereditary, for whole families (strains) become 

 undersized and others as much above the medium. 



Energy of growth not to be confused with bodily or func- 

 tional activity. While the larger animal of his kind, whether 

 it be the individual or the strain, represents the greater energy 

 of cell division in body building, it by no means follows that 

 the body when built will possess a greater degree of activity 

 than will its normal or smaller neighbor ; indeed, the opposite is 

 likely to be true, because the larger body works at greater dis- 

 advantage, having greater inertia to overcome and more dead 

 weight to carry about. This is eminently true of all animals 

 whose service involves transporting the body from place to 

 place, as among horses. It is manifestly impossible for a heavy 

 horse to equal a light one in speed without the expenditure of 

 far more power in doing it. This is not only because of the 

 extra weight but because of mechanical disadvantages as well. 

 In activities not involving motion this difference in size, within 

 reasonable limits, does not exist ; small men, for example, are 

 doubtless no more and no less intellectual than are large ones. 



Importance of morphological variation. Next to those of color, 

 differences in size are the most noticeable of all variations ; but 

 they are by no means the most significant, and their importance 

 is likely to be greatly overestimated. Except in a few instances, 

 as with draft horses, mere size is of far less consequence than 

 is commonly supposed. 



Generally speaking, it is some quality other than bulk that 

 determines value, and it will be fortunate for breeding when the 

 popular notion that " the biggest is the best " shall have passed 

 away. The largest apple is not the best for eating, nor the 

 largest bull the best for breeding purposes. However, this does 

 not free the student and breeder from considerations of size, 



