CONTENTS 



XV11 



factors : C0 2 -concentration and light — II. Variable factors : C0 2 - 

 concentration and temperature — III. Variable factors : light and 

 CO a -concentration ; light carried through half a cycle and C0 2 - 

 concentration in two stages — IV. Variable factors ; light and 

 temperature ; light of two intensities and temperature carried 

 through a cycle — V. Three variable factors : light, COa-concen- 

 tration, and temperature — VI. Four variable factors : COa-con- 

 centration, light, temperature, and tonic condition . 



252 



CHAPTER XXVIII 



GENERAL REVIEW 



266 



