140 GROWTH 



essential nature of the mechanism controlling the develop- 

 mental process. Is morphogenesis primarily the result of struc- 

 ture or of function? Arguments of varying plausibility have 

 been offered on both sides of the question. Roux held that the 

 functional factor is important only in the later phases of mor- 

 phogenesis. It seems to be largely a question of definition of the 

 terms structure and function. My own view is in agreement 

 with those who hold that in a broad sense the two are insepa- 

 rable and indispensable. As expressed by Wallis, 50 "Function is 

 only structure in action, but the structure which is not in action 

 is about as futile as the function which has no substratum." 



Both physics and chemistry are now interpreting material 

 phenomena in terms of structure, — molecular, atomic, and elec- 

 tronic j but with this structure there are always associated energy 

 and movement, which correspond to function. Similarly in the 

 living organism we have to deal ultimately with the arrangement 

 and the movements of material particles, i.e., with structure and 

 function reduced to their lowest terms. And therefore, as it 

 seems to me, in solving the problems of morphogenesis we have 

 both need and ample room for cooperation among biologists 

 and others interested in all of the various aspects of the ques- 

 tion. It is a problem primarily for the morphologists and the 

 physiologists 5 but they need also the help of mathematics, 

 physics, and chemistry. It is a fascinating field of great impor- 

 tance in which we may all join hands as "companions in zealous 

 research." 



