6 Contents 



CHAPTER PAGE 



III. The Absorption of Nitrogen and the Con- 



struction of Nitrogenous Substance . 323 



IV. The Progress of our Knowledge of the 



R6le of the Constituents of the Ash of 



Plants 357 



V. The Discovery of Chemosynthesis . . 368 



VI. The Development of Knowledge of the 



Metabolic Processes 37 2 



VII. The Development of Knowledge of the 

 Metabolic Processes {continued) : Diges- 

 tion. The Nature of Nutrition . . 40° 

 VIII. The Development of the Modern Idea of 



THE CATABOLIC PROCESSES AND THE INTERNAL 



Energy Relations of Plants . . . 4*9 



IX. The Influence of the Study of the Nutri- 

 tion of Heterotrophic Plants on the 

 Progress of Knowledge of the True 

 Nature of the Food of Plants . . . 43 1 

 X. The Problems of Growth and its Associated 



Conditions 44 2 



XI. The Development of the Theory of Special 

 Sensitiveness under the Influence of 

 the 'Origin of Species' .... 458 



General Conclusion 5 QI 



Bibliography 5° 8 



Index 539 



