英文科学读本 第三册·Lesson 57 The Bark

Lesson 57 The Bark

We have had a lesson today, Norah, about the tree's coat, said Willie.

The tree's coat, said Norah. "What do you mean?"

Come into the garden, said Will, "and we'll show you. Look at this old tree. How rough and gnarled its stem and branches look. This outside part of the tree is quite different from the rest of the woody stem. We call it the bark. This is what I meant by the tree's coat."

Will is quite right, said Fred, "only I should perhaps call it, as teacher did, a double coat, for there is an inner one beneath this rough one on the outside."

But let us look at some of the other plants in the garden, Fred continued. "I can easily peel off from any of them an outer skin or covering. It is not so thick, of course, as the tree's coat, but it is the same sort of thing. It covers the plants just as the skin covers our bodies. It is in each case the bark of the plant."

The outer bark which we can see is, of course, thicker and coarser than the one beneath it. We might call this the tree's greatcoat. The cork which we use for so many purposes is the outer bark of a kind of oak tree which grows in Spain. These trees are grown only for their bark, which is stripped off them from time to time.

The bark of the oak, larch, chestnut, willow, and birch, when ground small and steeped in water, gives a liquid called ooze, which is used in tanning leather.

The outer bark of certain trees is used for dyeing; and the valuable medicine, quinine, is made from the bark of the cinchona tree.

The inner bark is an entirely different substance. Teacher showed us some strips of the inner bark of the bass-wood tree, and father has lent me this to show you now.

Why, Fred, said Norah, "this is the common bass, that father uses for tying up his plants in the garden."

Yes, Norah, and this common bass—or bast—is really the inner bark of the bass-wood, as I said just now.

Now I want to give you one thing to think about, he added. "Long, long ago, before people had paper, they used to write on thin sheets of this bass to make their books. The Latin name for book is liber. This is why bass is sometimes called liber."

SUMMARY

The bark is the outside coat of the plant. The bark of trees is thick. Cork is the bark of a tree. The bark of the oak and other trees is used in tanning. The bark of some trees is used for dyeing; that of others for medicine.