(A^- I 



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♦I 



VOLUME 19 



NUMBER 1 



. JA:N^UAIIY, 1916 



CONTAINING 



The Theories of Photosynthesis in the Light of Some New Facts 



H. A. Spoehr 1 



On the Behavior of an Excised Branch of the Sahuaro 



Raymond J. Pool 17 



Books and Current Literature 23 



Notes and Comment 26 



PUBLISHED MONTHLY 



OFFICE OF PUBLICATION 



2419-21 Greenmount Ave. 



BALTIMORE, MD. 



EDITORIAL OFFICE 



TUCSON, ARIZONA 



pnteretl as second-cla.ss matter March 9, 1912, at the post office at Baltimore, Maryland, under the Act of July 16, 1894 



