1915^ Outline on the Theory of Descent 25 



ping out of something which inhibited the appearance of 

 these characters so long as it was present. This is just the 

 view proposed by William Bateson in his presidential ad- 

 dress to the British Association for the Advancement of 

 Science last summer at its meeting in Australia. 



Certainly this is not a very satisfying theory, still it is not 

 altogether unthinkable as the philosophers have a fondness 

 for saying. At any rate we have at least one striking analogy 

 — the mature man develops from a fertilized egg so small that 

 it is scarcely visible to the unaided eye; nevertheless, there 

 are collected within this small scope representive units, 

 which we call determiners, for every important physical, 

 mental and moral trait that constitutes the fully developed 

 man. 



CONCLUSION 



The hypothesis of descent is thus in a somewhat un- 

 satisfactory state. The newer researches have made old 

 views untenable without in themselves furnishing a complete 

 explanation. Such periods, however, are not infrequent in 

 the history of science. At the present time, there is little that 

 can be asserted with any degree of positiveness beyond the 

 fact that somehow or other evolution has occurred. This 

 central fact has been strengthened with the passage of the 

 years, although as regards just what has taken place, how, 

 and by what means, they have left us pretty much as we were 

 in 1859 after the appearance of Darwin's "Origin." 



These years of research have been wonderfully effective 

 in untangling the factors in a most complex problem and the 

 reason why success has not been completely attained seems 

 to me to lie principally in the fact that the problem was more 

 complex than the workers have, hitherto, realized. With the 

 experimental method added to the equipment of the investi- 

 gator, which, in my judgment has been hitherto limited too 

 much to the microscope, and with the concise results of 

 Mendelism, mutation and pure line investigation, it seems to 

 me not extravagant to expect a comprehensive explanation of 

 the problem at a date not very far distant. 



