THE INFLUENCE 



LIGHT AND DARKNESS 



GROWTH AND DEVELOPMENT 



BY 



DANIEL TREMBLY MACDOUGAL, Ph.D. 



LIBRARY 

 NEW YORK 

 BOTANICAL 



QAROfiN 



Published by the aid ov the 



David Lydig Fund 



Bequeathed by Charles P. Daly. 



NKW YORK: 

 1903 



