CONTEXTS xiii 



CHAPTER VH 

 ACTION OF LIGHT UPON PROTOPLASM 



PAGE 



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



2. The Chemical Action of Light upon Xon-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 * . . .180 



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 



(L The Mechanics of Response to Light .... 207 



Summary of the Chapter . 210 



Literature -1- 



