CHAPTER III.— CELL CONTENTS. 
In active cells there are generally a nuinber of structures 
sharply differentiated from the ground substance. To the 
latter Strasburger has given the name cytoplasm, in order to 
distinguish between protoplasm in its undifferentiated state, 
and that containing the various products formed in and by it. 
The structures are divided into two classes, active and passive ; 
the former are similar in nature to cytoplasm, and are the 
nucleus, chlorophyll grains, color grains, and starch-builders, the 
last three being also known as plastids. The passive structures 
are those which may be formed at any time in the cell, and in 
comparison with the former class are less active in carrying on 
the life processes. These are protein or aleurone grains, starch 
grains, globoids, and crystals. In addition to these definitely 
organized structures, there is another large class, no less impor- 
tant but of less definite structure, which may be termed organic 
in distinction from organized. For convenience of description 
the entire cell contents may be tabulated as follows : 
Cytoplasm. 
Nucleus. 
Active. 
Plastids. 
Enclosed structures. 
Starch grains. 
Passive. 
Cell Contents. Aleurone grains. 
Organic Acids. 
Dextrine, Inulin, Gums. 
| Amides. 
Remaining contents of less mug oe 
A Ee RS po oe ory Oils, fixed and volatile. 
Resin. 
Glucosides and Alka- 
loids. 
Crystals and Cell Sap. 
