Xviii CONTENTS. 



PAGE 



Classification of the Principal Organic Products 357 



Products free from Nitrogen , 357 



Carbohydrates 357 



Vegetable Acids 360 



Fats, or Glycerides . 360 



Certain Astringents 361 



Glucosides 362 



Ethereal Oils 362 



Resins and Balsams 363 



Products containing Nitrogen 363 



Albumin-like Matters 363 



Asparagin 364 



Alkaloids .365 



Unorganized Ferments 365 



RESPIRATION 367 



Measurement of Respiration 367 



Plants in Dwelling-houses 368 



Relations of the Carbonic Acid given off in Respiration to the Oxy- 

 gen absorbed 368 



Influence of Temperature and Light upon Respiration o69 



Resting State 369 



Respiration accompanied by an Evolution of Heat 370 



Intramolecular Respiration 370 



CHAPTER XII. 



VEGETABLE GROWTH. 



Nature of Growth 373 



Cell-division 374 



In the Development of Stomata 376 



In Cambium 377 



In the Development of Pollen-grains 379 



In Plant-hairs 380 



Directions in which the new Cell-wall may be laid down 380 



Growth of the Cell-wall 382 



Measurement of Growth 383 



Conditions necessary for Growth 384 



Relations of Growth to Temperature 385 



To Light 387 



To Supply of Oxygen 388 



Periodical Changes in the Rate of Growth 389 



Properties of New Cells and Tissues 389 



Tensions in the Cell-wall 390 



Tension of Tissues 390 



Geotropism 392 



Heliotropism , = . . 392 



Hydrotropism 393 



