THE LIFE OF A PRIMROSE. 
159 
In the orange-pulp these cells contain only sweet 
juice, but in other parts of the orange-tree or any 
other plant they contain a sticky substance with little 
grains in it. This substance is called " protoplasm," 
or the first form of life, for it is alive and active, and 
under a microscope you may see in a living plant 
streams of the little grains moving about in the cells. 
Now we are prepared to explain how our plant 
grows. Imagine the tiny primrose plantlet to be made 
up of cells filled with active living protoplasm, which 
drinks in starch and other food from the seed-leaves. 
In this way each cell will grow too full for its skin, 
and then the protoplasm divides into two parts and 
builds up a wall between them, and so one cell be- 
comes two. Each of these two cells again breaks up 
into two more, and so the plant grows larger and 
larger, till by the time it has used up all the food in 
the seed-leaves, it has sent roots covered with fine 
hairs downward into the earth, and a shoot with be- 
ginnings of leaves up into the air. 
Sometimes the seed-leaves themselves come above 
ground, as in the mustard-plant, and sometimes they 
are left empty behind, while the plantlet shoots through 
them. 
And now the plant can no longer afford to be idle 
and live on prepared food. It must work for itself. 
Until now it has been taking in the same kind of 
food that you and I do; for we too find many seeds 
very pleasant to eat and useful to nourish us. But 
now this store is exhausted. Upon what then is the 
plant to live? It is cleverer than we are in this, for 
while we cannot live unless we have food which has 
