4 THE PROBLEMS OF EVOLUTION 



of phylogeny in an effort to determine the general 

 laws which govern the occurrences in the organic 

 world as evolution progresses. In the latter case, 

 of course, we risk departing rather too widely 

 from the solid ground of a specific problem in 

 phylogeny but any inquiry worthy of attention 

 must be founded upon a background of biological 

 facts which should serve as an adequate guaranty 

 of its scientific soundness and protect it against 

 the stigma of philosophic insecurity. 



It is unnecessary in a study of this kind, which 

 is avowedly an attempt to approach the problems 

 of species formation and general organic evolution 

 in the broadest possible way, to delve into the 

 past history of the subject in detail. Anyone who 

 is interested in it will undoubtedly be thoroughly 

 acquainted with that history so that a general 

 survey may be dispensed with. 



One conspicuous controversy has come down to 

 us from the past which, in final analysis, colors 

 every consideration of our problem that has yet 

 appeared. This controversy is best labelled with 

 the familiar term, inheritance of acquired char- 

 acters. Of it so much has been written that again 

 it is unnecessary to go into the details of past 

 treatment, but it establishes the point of depar- 

 ture for the critical portion of our study of evolu- 

 tionary processes. It has raged for many years 

 through the proposal of all existing theories of 



