222 HOW CROPS GROW. 
tinguishing their life, and by whose expansion or multipli- 
cation all growth takes place. Then will follow an account 
of the complex parts of the plant—its Compound Organs 
—which are built up by the juxtaposition of numerous 
cells. Of these we have one class, viz.: the Roots, Stems, 
and Leaves, whose office is to sustain and nourish the Indi- 
vidual Plant. These may be distinguished as the Vege- 
tative Organs. The other class, comprising the Flower 
-and Fruit, are not essential to the existence of the individ- 
ual, but their function is to maintain the Race. They are 
the Reproductive Organs. 
CHAPTER II. 
THE PRIMARY ELEMENTS OF ORGANIC STRUCTURE. 
a, 
THE VEGETABLE CELL. 
One of the most interesting discoveries that the micro- 
scope has revealed, is, that all organized matter originates 
in the form of minute vesicles or cells. If we examine by 
the microscope a seed or an egg, we find nothing but a 
cell-structure—an assemblage of little globular bags or 
vesicles, lying closely together, and more or less filled 
with solid or liquid matters. From these cells, then, comes 
the frame or structure of the plant, or of the animal. In 
the process of maturing, the original vesicles are often 
greatly modified in shape and appearance, to suit various 
purposes; but still, it is always easy, especially in the 
plant, to find cells of the same essential characters as those 
occurring in the seed. 
