CONTENTS 



CHAPTER X 



PAGE 



INTRODUCTION: ON NORMAL GROWTH .... 281 



CHAPTER XI 



EFFECT OF CHEMICAL AGENTS UPON GROWTH 



1. Effect of Chemical Agents upon the Rate of Growth . . . 293 



1. The Materials of which Organisms are composed . . . 294 



a. Analysis of the Entire Organism ..... 296 



b. Detailed Account of the Various Elements used as Food 304 



Oxygen, 304; Hydrogen, 306; Carbon, 306; Nitro- 

 gen, 307 ; Phosphorus, 313 ; Arsenic, Antimony, 

 and Bismuth, 314; Sulphur, 314; Chlorine, 316; 

 Bromine, 316; Iodine, 317; Fluorine, 317; Lith- 

 ium, 318; Sodium, 318; Potassium, 318; Rubidium 

 and Caesium, 320; Strontium, 321 ; Manganese, 321 ; 

 Iron, 321 ; Magnesium, 323 ; Silicon, 324 ; Copper, 

 324. 



2. The Organic Food used by Organisms in Growth . . . 324 



a. Fungi 324 



b. Green Plants 326 



c. Animals 327 



Amoeba, 328; Amphibia, 329 ; Mammals, 330. 



3. Growth as a Response to Stimuli 331 



a. Acceleration of Growth by Chemical Stimulants . . 331 



b. The Election of Organic Food 333 



2. Effect of Chemical Agents upon the Direction of Growth Chemo- 



tropism 335 



1. Chemotropism in the Tentacles of Insectivorous Plants . 335 



2. Chemotropism of Roots 336 



3. Chemotropism of Pollen-tubes 337 



4. Chemotropism of Hyphse 340 



5. Chemotropism of Conjugation Tubes in Spirogyra . . 342 

 Literature 343 



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