SOURCES OF CHANGE 55 



problem seems, however, to be solved in a general 

 way by Osborn's tetrakinetic theory. 



Osborn recognized the failure of evolutionary 

 theory to accord with the evident facts of evolu- 

 tionary progress, and logically concluded that the 

 explanation of evolution "must lie somewhere 

 within the actions, reactions, and interactions of 

 the four physico-chemical complexes, namely, the 

 physical environment, the developing organism, 

 the heredity-chromatin, the living environment, 

 because these are the only reservoirs of matter and 

 energy we know of in life history." ^ His last 

 clause is worthy of note. These factors are the 

 very foundation of life, so far as we can determine. 

 How can they fail to be at the same time the source 

 of organic change.^ Yet this does not meet the 

 diflficulty of specific points of relationship and he 

 continues: "While it is possible that the relations 

 of these four energy complexes will never be 

 fathomed, it is certain that our search for causes 

 must proceed along the line of determining which 

 actions, reactions, and interactions invariably pre- 

 cede and which invariably follow those of the body 

 cells (Lamarckian view) or those of the chromatin 

 (Darwin- Weismann view)." ^ 



This is as far as we can carry an inquiry into the 

 cause of variations at the present time. As long as 

 we pursue our investigations on the mechanistic 



* Origin and Evolution of Life, p. 145, 1917. ^ Op. cit., p. 145. 



