CONTENTS xiii 



CHAPTER VII 

 ACTION OP LIGHT UPON PROTOPLASM 



PAGE 



1. The Application and Measurement of Light .... 154 



2. The Chemical Action of Light upon Non-living Substances . 161 



1. The Synthetic Effects of Light 162 



2. Analytic Effect of Light 163 



3. Substitution Effects of Light 164 



4. The Isomerismic and Polymerismic Changes produced by Light 164 

 3. The Effect of Light upon the General Functions of Organisms . 166 



1. Effect of Light upon Metabolism .. .166 



a. The Thermic Effect of Light on Metabolism . . 166 



b. The Chemical Effect of Light on Metabolism . . 170 



2. Vital Limits of Light Action on Protoplasm . . . 171 



3. Effect of Light upon the Movement of Protoplasm . . 175 



a. Effect of Low Intensity of Light on Movement Dark- 



rigor 175 



b. Effect of High Intensity of Light on Movement 



Light-rigor ........ 178 



4. Control of the Direction of Locomotion by Light Phototaxis 



and Photopathy IbO 



1. False and True Phototaxis 181 



2. Distribution of Phototaxis and Photopathy .... 182 



a. Protista 182 



b. Cells and Cell-organs 189 



a. Chlorophyll Bodies . . . . . .189 



/3. The Rearrangement of Pigment in Animal Cells 



in Response to Light 192 



y. The Migration of Pigment Cells in the Metazoan 



Body 193 



c. Metazoa 194 



3. The General Laws of Phototaxis and Photopathy . . 196 



a. The Sense of the Response 196 



b. The Effective Rays 201 



c. Phototaxis vs. Photopathy . . . . . . 203 



d. The Mechanics of Response to Light .... 207 



Summary of the Chapter 210 



Literature 212 



