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THE ROLE OF NITROGEN AND ITS COMPOUNDS IN 

 PLANT-METABOLISM. 



Part i. — Historical. 



By James M. Petrie, D.Sc, F.I.C., Linnean Macleay Fellow 

 of the Society in Bio-Chemistry. 



(From the Physiological Laboratory of the University of Sydney.) 



CONTENTS. 



Introduction. 



The Source of the Nitrogen of Plants. 



The Nitrogen of the Soil. 

 The Relation of Protein to the Non-Nitrogenous Reserve-Material. 

 Absorption of Nitrogenous Food. 

 Protein Synthesis in the Plant. 

 Nitrogenous Reserve Materials. 



The Nitrogen Compounds in Seeds — Protein, Non-protein. 

 The Bio-Chemistry of Germination. 



Enzymes, Katabolism, Anabolism. 



Introduction. — In the days of Liebig the aims of organic 

 chemistry were to examine the substances comprising the structure 

 of living things and the products of their metabolism. Liebig's 

 great work was the building of the foundation of vegetable 

 chemistry. In the long interval which has since elapsed chem- 

 istry has chiefly been employed in perfecting its methods, and 

 with the new century it rises again and seeks its first love, biology, 

 under the new name of Bio-Chemistry. 



It is by the exact quantitative methods of physical science that 

 most of the recent advances in biology have been possible, and 

 indeed it is quite evident from a general survey of the current 

 literature that the physiology of plants and animals is progressing 

 along the lines of pure chemistry and physics. It is now fully 



