14 TYPES OF BRITISH PLANTS 
work. Here we need only notice that they are ready. 
Corpuscle, by the way, 1s a small body, a long word for 
a diminutive article. 
As the cell-wall expands—and how fast they expand 
you will realise when you remember that every cell in 
a full-grown leaf was also present in the bud, and each 
cell has to grow as the leaf expands—the protoplasm 
which once filled it now only lines it, and the interior 
is filled with the cell sap, chiefly water, but containing 
various substances, such as sugar and starch, dissolved 
within it. This sap acts as the carrier from one work- 
shop to the other, for the cell-wall has the property of 
allowing it to pass through, and is thus useful to the 
plant. From the sap of various plants, such as the sugar- 
cane, the sugar-maple, and the beet, we get sugar. 
Looking through more cells we may notice, in the 
chlorophyll corpuscles, certain grains of another sub- 
stance, starch, which is being formed as a reserve store 
of material for building up new cell-walls when required. 
If we also examine, say, 
a seed, or a slice of potato, 
under the microscope, we 
shall find in certain cells 
quite large grains of starch, 
all ready for the next year’s 
sprouting. In.some trees, 
such as the sago-palm, this 
is stored in such quantities 
in the pith that with very 
little preparation we are 
able to eat it in sago and 
tapioca puddings. 
STARCH GRAINS MAGNIFIED. Beside this reserve, there 
