“Each seed has a small plant with a long root, and small, stout green leaves. Look at the roots and tell me what you see?”
“They are covered with silky stuff,” said Frank.
“Yes. Now take this glass, which will make things look bigger than they really are, and look at the roots once more.”
“The silky stuff is a number of fine hairs,” said Frank.
THE OTTER
FIELD-MICE
“That is quite right, Frank,” said Uncle George. “These are the root-hairs. Each of these hairs is a long bag or sac, of very thin skin. It is filled with a liquid called sap, which is slightly denser, or heavier, than the water in the blotting-paper. Now, do you see how a plant takes food from the soil, when it is growing in the garden or in a field?”
“Yes, I think I do,” said Frank. “The water in the soil contains very little plant-food. The water inside the tiny sac contains very much.”