138 DOCTRINE OF EVOLUTION 



the history of the game cock, which has nearly doubled 



in height since 1850, while at the same time its slender 



legs, long spurs, and other qualities have been perfected 



for the cruel sport for which it has been bred. Again, 



the wild rock pigeon seems to be the ancestral form 



from which the fantail and pouter and carrier-pigeon 



with their diverse characters have taken their origin. 



It is true that some biologists have urged certain 



K technical objections to the employment of domesticated 



\ animals and their history as analogies to the processes 



\ and results in wild nature. To my mind, however, 



artificial selection is truly a part of the whole process 



^of natural selection. Man is but one element of the 



(environment of tame forms, and his fancy or need is 



' therefore one of the varied series of external criteria 



that must be met if survival is to be the result ; failing 



this, elimination follows as surely as under the conditions 



of an area uninhabited or uninfluenced by mankind. 



Congenital variation is real, selection is real, and the 



heredity of the more fit modification is equally real. 



Surely Darwin was right in contending that the facts 



of this class amplify the conception of natural selection 



developed on the basis of an analysis of wild life. 



Knowing the elements of the selective process, it is 

 possible to analyze and to understand many significant 

 phenomena of nature, and to gain a clearer conception of 

 the results of the struggle for existence, especially when 

 the human factor is involved. Let us see how much 

 is revealed when the foregoing results are employed in 

 a further study of some of nature's vital situations. 



