THE MUTATION THEORY 557 



ficial' selection may differ from natural selection in the characters 

 that are perpetuated, but the method is the same. In nature only 

 those characters can be selected that are useful to the species itself. 

 It would, therefore, be impossible for natural selection to modify 

 a species to its own disadvantage or to the advantage of another 

 species, save as this might be an incidental result. Under arti- 

 ficial selection, however, animals are often modified in ways that 

 would be injurious were it not for the protection afforded them by 

 man. While this difference between artificial and natural selec- 

 tion must be recognized, it is perhaps the more significant that the 

 selective process can be made to work in another way than it does 

 in nature. If man chose to select for the good of the organism 

 rather than for his own, he could no doubt produce results parallel 

 to those of nature. 



A selective process, or survival of the fittest, undoubtedly func- 

 tioned in the human species in the past. At times it requires a 

 good deal of optimism to beUeve that it has ceased to function. 

 The declaration that it should apply in civilized life is perhaps one 

 of the chief causes for the offense that has been given by some 

 biologists and others to individuals who are laboring for an increase 

 of human sympathy. Although the problem is a complex one, it 

 is perhaps a sane view that mankind, having arisen by evolution, 

 was subject in the past to the law of tooth and claw, and that dis- 

 couraging evidences of this condition survive. The finer human 

 relationships, however, rest upon a basis of cooperation rather 

 than of conflict. Perhaps the evolutionary beginnings of these 

 relationships may be seen in parental care and in the relationships 

 of mutual helpfulness that exist in family life. 



The Mutation Theory 



Historical. — During the decades immediately following the 

 pubUcation of '' The Origin of Species " (1859), biological investi- 

 gation consisted principally in extensions of the Doctrine of 

 Evolution and of Natural Selection. It was hoped that unques- 

 tionable phylogenetic relationships could be estabhshed for the 

 Animal Kingdom (c/. Fig. 117, p. 240); and natural selection was 

 accepted as the all-sufficient cause of evolution. In the last decade 

 of the century, however, it became apparent that mere confirma- 

 tions of the general process of evolution were no longer profitable, 



