xxi EVOLUTION OF EVOLUTION THEORIES 423 



of advantageous variations and natural elimination of 

 those less fit, explain the general transformation and 

 adaptation of species, as well as the general progress from 

 simpler to higher forms of life. 



This theory that favourable variations may be fostered 

 and accumulated by nature 1 selection till useful adapta- 

 tions result is the chief characteristic of Darwinism. Of 

 this theory Prof. Ray Lankester says : 



" Darwin by his discovery of the mechanical principle of organic 

 evolution, namely, the survival of the fittest in the struggle for 

 existence, completed the doctrine of evolution, and gave it that 

 unity and authority which was necessary in order that it should 

 reform the whole range of philosophy." 



And again he says : 



" The history of zoology as a science is therefore the history of 

 the great biological doctrine of the evolution of living things by 

 the natural selection of varieties in the struggle for existence, 

 since that doctrine is the one medium whereby all the phenomena 

 of life, whether of form or function, are rendered capable of explana- 

 tion by the laws of physics and chemistry, and so made the subject- 

 matter of a true science or study of causes." 



We have quoted these sentences because they illustrate 

 the exaggeration to which enthusiasm for a great theory 

 may lead a strong intellect. Beside them we would place 

 a few sentences from Samuel Butler, which will serve to 

 show that the most brilliant critics of Darwinism may 

 also be extreme. Perhaps the contrast between our two 

 quotations may stimulate the reader to inquire into the 

 matter for himself. 



" Buffon planted, Erasmus Darwin and Lamarck watered, 

 but it was Mr. Darwin who said ' That fruit is ripe,' and shook 

 it into his lap. . . . Darwin was heir to a discredited truth, and left 

 behind him an accredited fallacy. . . . Do animals and plants grow 

 into conformity with their surroundings because they and their 

 fathers and mothers take pains, or because their uncles and aunts 

 go away ? . . . The theory that luck is the main means of organic 

 modification is the most absolute denial of God which it is possible 

 for the human mind to conceive. . . ." 



7. Darwin's Fellow-workers. But we must bring this 

 historical sketch to a close by referring to four of the 



