The 



Pi ant World 



A Magazine of General Botany 



VOLUME 16 

 K U M B E R 4 

 APRIL 1913 



OOWTAININO 



Some Bacteriological Studies of Old Soils 



By L. T. Sharp 101 



The Occurrence of Callose in Root Hairs 



By Charles S. Ridgway 116 



Books and Current Literature 123 



Notes and Comment 127 



PXTBLISHED MONTHLY 



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 BALTIMORE. MD. 



EDITORIAL OFFICE 

 TUCSON. ARIZONA 



Entered as neoDd-cUas matter March 9, 1011. at the post ofiiee at Baltimore. Maryland, undar tha Aet of July IC 18V4 



