bread. Each at once turned dark blue on being dipped into the liquid.

“Now, boys,” he said, “what do you learn from this?”

“The food store in bulbs and corms is the same as that in seeds,” said Tom.

“The food supply of the bulb is contained in the thick, fleshy scale-leaves, while in the corm it is in the stem,” said Frank.

“Very good,” said Uncle George. “It also shows us, I think, that we ourselves owe a great deal to the plant world.”

Exercises on Lesson II.

1. Split an onion (or tulip bulb) down the centre, and compare it with the snowdrop bulb. Draw it, giving special attention to the middle part.

2. Take a potato and a crocus corm. Observe them both carefully, and find out (1) how they resemble each other, and (2) how they differ.

3. Explain how it is that a hyacinth grows so well in water.

4. Take any underground stem (e.g., iris or Solomon’s seal) and compare it with a crocus corm. Notice the marks of underground scale-leaves on the former.

III.—WHAT GOES ON INSIDE A PLANT.

“We have seen how an ordinary twig is built up,” said Uncle George. “Let us now try to find out what goes on inside the twig; and in order to do this we shall have to perform one or two simple experiments.”

Uncle George took two wide-mouthed glass jars. They were both perfectly dry, and each could be closed with a large, tight-fitting cork. He placed some fresh green leaves inside one of the jars. The other remained empty. Then both jars were tightly corked up, and both corks covered outside with wax.

First Experiment.

“That is experiment number one,” he said, as he placed both jars in the window.

He next took a small plant which was growing in a pot. He wrapped the pot up in thick, dry paper, so that the paper covered up everything but the plant. The edges of the paper were tied tightly round the lower part of the stem of the plant with a string. The plant was put in the window, and over it Uncle George placed a glass bell-jar.

Second Experiment.

“The third experiment is much simpler,” he said. “You see I just put one of the willow twigs into a glass half filled with water, and into the water I pour some red ink. Frank, place a white pansy in the coloured water beside the willow twig.”

Uncle George’s fourth experiment was as follows:—

He placed four willow twigs in a glass of water. But from two of these twigs he first removed a broad ring of the bark and outer layers, leaving about an inch of the wood bare near the lower end of the twig.

“Now,” said he, “we will come back in about an hour, and I think we shall find that some change has taken place in each of our first three jars.

“The fourth glass one will have to be left for several weeks; and we must take care to keep water always in the glass containing these four twigs.”

About an hour afterwards, Uncle George and the boys came to look at the experiments.

“Let us examine experiment one first,” said Uncle George.

“The empty jar is just the same as when we put it there,” said Tom. “The jar containing the leaves is all dimmed, and there are tiny drops of water on the inside of it.”

“Where did that water come from, Tom?”

“It must have come out of the leaves.”

“Exactly so! Now look at the second experiment, and you will see that the