THE 



AMERICAN NATURALIST 



Vol. XLV January, 1911 No. 529 



ORGANIC RESPONSE 1 



D. T. MACDOUGAL, Ph.D., LL.D. 

 Desert Laboratory, Tucsosr, Ariz. 



At no time in the history of natural science has such 

 a large share of thought and research energy been di- 

 rected to the solution of evolutionary problems as at pres- 

 ent. Methods of work, plans for experimentation and 

 modes of interpretation have recently undergone such 

 rapid development and improvement that our potenti- 

 ality for solving questions in heredity and origination is 

 vastly greater than even at such recent date as the be- 

 ginning of this new century. With increased facility 

 in attack has also come wider vision and altered view- 

 points with regard to almost all phases of biology. 



Biological thought once quickened and broadened by 

 evolutionary ideas was by this same means led to be- 

 come entangled in a maze of illusive assumptions as to 

 purpose and plan in organisms from which it is being but 

 slowly freed, to view functions as inevitable reactions, 

 however complex they may be. The variables included 

 in the equations of protoplasmic action are numerous 

 and large, but they do not exceed the undefined prin- 

 ciples of osmotic action, surface tension and unknown 

 phases of association and dissociation that are concerned 

 in the interplay of substances in the cell, and upon which 



Presidential address, Society of American Naturalists, Ithaca, New 

 York, December 29, 1910. 



