PART I. 



PHYSIOLOGY. 

 CHAPTER I. 



PROTOPLASM.* 



1. In the study of plant life and growth, it will be found 

 convenient first to inquire into the nature of the substance 

 which we call the living material of plants. For plant growth, 

 as well as some of the other processes of plant life, are at bottom 

 dependent on this living matter. This living matter is called in 

 general protoplasm. 



2. In most cases protoplasm cannot be seen without the 

 help of a microscope, and it will be necessary for us here to em- 

 ploy one if we wish to see protoplasm, and to satisfy ourselves 

 by examination that the substance we are dealing with is 

 protoplasm. 



3. We shall find it convenient first to examine protoplasm in 

 some of the simpler plants ; plants which from their minute size 

 and simple structure are so transparent that when examined with 

 the microscope the interior can be seen. 



For our first study let us take a plant known as spirogyra, 

 though there are a number of others which would serve the pur- 

 pose quite as well, and may quite as easily be obtained for 

 study. 



