FACTS AND FACTORS OF DEVELOPMENT 41 



ment but not until all parts are formed and 

 connected and all their functions are synthe- 

 sized does the new function, vision, spring into 

 existence. Undoubtedly the same is true of 

 many other complex functions which have no 

 existence until all their constituents are pres- 

 ent and integrated, when they suddenly 

 appear. 



Much less attention has been paid to the de- 

 velopment of functions than to the develop- 

 ment of structures, and consequently it is not 

 possible to describe the former with the same 

 degree of detail as the latter. But in spite of 

 the lack of detailed knowledge regarding the 

 development of particular functions the gen- 

 eral fact of such development is well estab- 

 lished. To what extent structures may modify 

 functions or functions structures, in the course 

 of development, is a problem which has been 

 much discussed, and upon the answer to it de- 

 pends the fate of certain important theories, 

 for example Lamarckism; but this problem 

 can be solved only by thoroughgoing experi- 

 mental and analytical work. In the meantime 

 it seems safe to conclude that living structures 



