SELECTION AND ITS IMPORTANCE 231 



be conserved by their being shut off from their species, or 

 by their species being shut off from them." Again he says: 

 "If a given number must die, that number must be singled 

 out upon some principle, and we cannot quarrel with the 

 principle in physical nature which condemns to death the 

 worst." Natural selection therefore represents a progressive 

 development, with each succeeding generation somewhat 

 stronger and better bred for meeting the requirements of 

 existence. An especially interesting phase of natural 

 selection is, that through it the species is developed so as to be 

 best adapted to its purpose and condition of living. 



Artificial selection involves the introduction of man. He 

 controls the matter of .selection, and thereby is able to cause 

 the animal to vary more or less from the parent type. In 

 the earliest times, no doubt man exercised some control over 

 the animals that he found useful, and caused changes in 

 their development. Thus man's ability to affect the pur- 

 pose and value of dumb animals must have appeared evident 

 to him long ago. The famous sculptures of Egypt and 

 Nineveh, dating back thousands of years, show that domestic 

 animals at that time must have been improved by man 

 through the practice of selection. The Bible has been 

 repeatedly quoted by writers on heredity, to show that the 

 influence of selection was recognized prior to the time of 

 Christ, as expressed in Genesis. Early writers like Plato, 

 Pliny, and Columella, all refer to the improvement of live 

 stock by selection. All through the intervening centuries 

 up to the present time, interesting references occur in history 

 of animal improvement being sought through selection. 



Methodical selection is" a term used by Darwin to express 

 the more systematic artificial process. In his most interest- 

 ing work on " Animals and Plants Under Domestication," 

 jbe presents much evidence to show the practical application 



