CONTENTS, xi 



BOOK III. 

 PHYSIOLOGY. 



CHAPTER I. 

 Molecular Forces in the Plant. 



FAGE 



Sect. I. The Condition of Aggregation of Organised Structures .... 663 



„ 2. Movement of Water in Plants 674 



„ 3. Movements of Gases in Plants 691 



CHAPTER II. 



Chemical Processes in the Plant. 



Sect. 4. The Elementary Constituents of the Food of Plants 694 



„ 5. Assimilation and Metastasis ' 703 



„ 6. The Respiration of Plants 721 



CHAPTER III. 

 General Conditions of Plant-life. 



Sect. 7. The Influence of Temperature on Vegetation . . . . . .725 



„ 8. Action of Light on Vegetation 737 



J, 9. Electricity 768 



„ 10. Action of Gravitation on the Processes of Vegetation 770 



CHAPTER IV. 



The Mechanics of Growth. 



Sect. ir. Definition 773 



Various Causes of Growth 775 



General Properties of the Growing Parts of Plants 778 



Causes of the Condition of Tension in Plants 787 



Phenomena due to the Tension of Tissues in the Growing Parts of Plants . 794 



Modification of Growth caused by Pressure and Traction .... 809 

 Course of the Growth in Length under constant External Conditions . .815 

 Periodicity of Growth in Length caused by the alternation of Day and 



Night 823 



Effect of Temperature on Growth 828 



Action of Light on Growth in Length. — Heliotropism . . . .832 



Action of Gravitation on Growth in Length. — Geotropism . . . . 839 



Unequal Growth 854 



