JOURNAL 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. VII FEBRUARY 19, 1917 No. 4 



BIOPHYSICS. — The living plant as a physical system. 1 Lyman 

 J. Briggs, Bureau of Plant Industry. 



In early investigations relating to the growth of plants, the 

 conception of a so-called " vital force" was frequently employed 

 in the interpretation of the observed phenomena. It was long 

 held, for example, that the organic substances found in plants 

 and animals were dependent in their formation upon the exist- 

 ence of vital forces, and that in consequence such products could 

 not be produced in the laboratory. The classical discovery of 

 Wohler that urea could be synthesized in the laboratory revo- 

 lutionized the conception that all animal and plant products are 

 dependent upon some vital force for their production. Since 

 that time many other organic substances found in or derived 

 from plants have been prepared synthetically. Many other 

 phenomena associated with plant growth and formerly attrib- 

 uted to the existence of some peculiar vital force have through 

 modern methods of investigation been satisfactorily explained 

 from physico-chemical considerations. Until matter in that 

 state which we term "living" can be synthesized, the doctrine of 

 vitalism can scarcely be said to have been disproved; but it is 

 surely being restricted more and more a's our knowledge of plant 

 phenomena increases. The situation at present may perhaps be 

 fairly summarized as follows: The mechanism of plant processes 



1 Address of the retiring President of the Philosophical Society of Washing- 

 ton, presented before the Society January 19, 1917. 



89 



