6 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 



with a large group of phenomena consistently arranged and properly 

 classified. The discussion which followed the publication of Darwin's 

 'Origin of Species ' lasted for nearly a generation, but it is now practi- 

 cally closed, so far as any attempt to discredit evolution as a true 

 scientific generalization is concerned. Scientists are no longer ques- 

 tioning the fact of evolution; they are busied rather with the attempt 

 to further explore and more perfectly understand the operation of the 

 factors that are at work to produce that development of animals and 

 plants which we call organic evolution." Maynard M. Metcalf, An 

 Outline of the Theory of Organic Evolution (1911), pp. xxii-xxiii. 



"Biologists turned aside from general theories of evolution and 

 their deductive application to special problems of descent, in order to 

 take up objective experiments on variation and heredity for their own 

 sake. This was not due to any doubts concerning the reality of 

 evolution or to any lack of interest in its problems. It was a policy 

 of masterly inactivity deliberately adopted; for further discussions 

 concerning the causes of evolution had clearly become futile until a 

 more adequate and critical view of existing genetic phenomena had 

 been attained." E. B. Wilson (address as president of the American 

 Association for the Advancement of Science, 1914). 



'The theory of development, as it was revived by Darwin nearly 

 half a century ago, is in its modern form prevailingly unhistorical. 

 True, it has forced beneath its sceptre the methods of investigation 

 of all the sciences which deal with the living world and to-day almost 



completely controls scientific thought And yet science does 



not sincerely rejoice in its conquests. Only a few incorrigible and 

 uncritically disposed optimists steadfastly proclaim what glorious 

 progress we have made; otherwise, in scientific as in lay circles, there 

 prevails a widespread feeling of uncertainty and doubt. Not as 

 though the correctness of the principle of descent were seriously 

 questioned; rather does the conviction steadily grow that it is 

 indispensable for the comprehension of living nature, indeed self- 

 evident. " Gustav Steinmann (translated by W. B. Scott from 

 Die Abstammungslehre [1908], pp. 1-2). 



"The many converging lines of evidence point so clearly to the 

 central fact of the origin of forms of life by an evolutionary process 

 that we are compelled to accept this deduction, but as to almost all 

 the essential features, whether of cause or of mode, by which specific 



