CONTENTS 



CHAPTER X 



PAGE 



Intkoduction I 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 



6. 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 



ft. The Election of Organic Food 333 



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



tropisra 335 



1. Chemotropisrn in the Tentacles of Insectivorous Plants . 335 



2. Chemotropisrn of Roots 336 



3. Chemotropism of Pollen-tubes 337 



4. Chemotropism of Hyphae 340 



5. Chemotropism of Conjugation Tubes in Spirogyra . . 342 

 Literature 343 



XV 



