TORREYA 



April, 1908 

 Vol. 8. No. 4. JBRARY 



BOTANY * NEW YORK 



T. u AT r. BOTANICAL 



By Herbert Maule Richards 



UaRUEN. 



It is in the field of physiology more than anywhere else, 

 perhaps, that the worker must humble himself before the 

 immensity of the problems before him ; that he must realize how 

 fragmentary is the most advanced knowledge of this subject. 

 The foundation stone of physiology is chemistry, and conse- 

 quently its advance must go hand in hand with the advance of 

 that science ; but there is also, it must be admitted, the element 

 of empiricism, which is an unfortunate necessity in any branch of 

 learning where any considerable mass of facts are not yet cor- 

 related. The greatest advances are made in the direction of 

 resolving this empirical information into more compact and 

 definite form, a task only possible by the accumulation and cor- 

 relation of great masses of data in connection with the more 

 definite information afforded by chemistry or physics and more 

 particularly modern physical chemistry. It is plain, then, that 

 we can never go ahead of the data afforded by these sciences, but 

 must always follow somewhat behind them. It must not be 

 supposed, however, that physiology is in a nebulous condition, 

 despite the fact that we are but on the margip of the unknown. 

 Distinct and creditable advances have been made since the days 

 when the knowledge of plant morphology and the chemistry of 

 Lavoisier made possible any reasonably satisfactory explanation 

 of the functions of plant organs. The establishment of a proper 

 understanding of how the plant obtains its food has been a matter 

 of the utmost importance, both from the development of theor- 

 etical physiology, and from the standpoint of practical use. We 



* A lecture delivered at Columbia University in the Series of Science, Philosophy, 



and Art, December 4, 1907, copyrighted and published by the Columbia University 



Press, February, 1908, and reprinted by permission in Torreya, beginning with the 



March number. 



^ [No. 3, Vol. 8, of Torreya, comprising pages 41-64, was issued March 27, 1908.] 



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