THE SOURCES OF 
THE 
NITROGEN OF VEGETATION; 
WITH SPECIAL REFERENCE TO THE QUESTION WHETHER PLANTS 
ASSIMILATE FREE OR UNCOMBINED NITROGEN. 
BY 
JOHN BENNET LAWES, F.BS., F.CS., 
JOSEPH HENRY GILBERT, Pu.D., F.B.S., F.CS., 
AND 
EVAN PUGH, Pz.D., F.C. 
From the PHILOSOPHICAL TRANSACTIONS.—Parr IT. 1861. ' 
LONDON: 
PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. 
1862. 
S 
