2 BOTANY. 



4. Living protoplasm possesses the power of imbibing 

 food in the condition of watery solutions. The water with 

 which plants are supplied in nature always contains a con- 

 siderable amount of soluble matter, most of which is good 

 food for protoplasm. The imbibition of watery food in- 

 creases the size of the protoplasm, and this is one of the 

 causes of growth in plants. Commonly there is a surplus 

 of imbibed material, and this is stored in the protoplasm 

 in the form of drops of greater or less size (the so-called 

 vacuoles), thus adding still more to the distension of the 

 protoplasm mass. (Fig. 1, «.) 



5. The most remarkable property of protoplasm is its 

 power of moving. Every mass of living protoplasm ap- 

 pears from observation to have the power under favorable 

 conditions of changing its form, shifting the positions of its 

 several parts, and in many instances of moving bodily from 

 place to place. That these movements are so generally 

 overlooked is due to the fact that in most cases they require 

 the aid of a good microscope, but with such an instrument 

 the student may find evidences of motion in the protoplasm 

 of every plant. 



6. The imbibition of food, and the various movements, 

 are affected by the temperature of the protoplasm. They 

 take place best in temperatures ranging from that of an 

 ordinary living-room to that of a hot summer day (20° to 

 35° C. = 68° to 95° Fahr.). A sudden change of tempera- 

 ture of even a few degrees will at once check or stop both 

 imbibition and movement; even a sudden jarring will for 

 a time stop both kinds of activity. 



Practical Studies. — In the study of protoplasm it is necessaiy to 

 be provided with a compound microscope. For convenience of 

 working, as well as for economy, the small instruments with short 

 tube, allowing easy use in a vertical position, are much to be pre- 



