9 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, s.) 
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 necessary 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- 
