“The fragrant lime,” said Miss Harson, “has a relative in Asia whose acquaintance I wish you to make, and you know it already in one of its products, which is common in every household.  It is also very fragrant—­or rather, I should say, it has a strong aromatic odor which is very reviving in cases of faintness or illness, although it has quite a contrary effect on insects, particularly on mosquitoes.  I should like to have some one tell me what this white, powerful substance is.”

This was quite a conundrum, and for a little while the children were extremely puzzled over its solution; but presently Clara asked,

“Do the moths hate it too, Miss Harson?  And isn’t it camphor?”

“Camphor doesn’t grow on a tree,” said Malcolm, in a superior tone; “it is dug out of the earth.”

“I have never read of any camphor-mines,” replied his governess, laughing, “and I think you will find that camphor—­which is just what I meant—­is obtained from the trunk of a tree.”

“Like India-rubber?” asked Edith.

“No, dear, not like India-rubber, for it grows in even a more curious way than that, masses of it being found in the trunk of the camphor tree—­not in the form of sap, but in lumps, as we use it.”

“I thought it was like water,” said Edith, in a puzzled tone.

“So it is when dissolved in alcohol, as we generally have it; but it is also used in lumps to drive away moths and for various other purposes.  But I will tell you all about the tree, which grows in the islands of Sumatra and Borneo and bears the botanical name Dryobalanops camphora.  The camphor is also called barus camphor, to distinguish it from the laurus, of which I will tell you afterward, and it is of a better quality and more easily obtained.  The tree grows in the forests of these East Indian islands and is remarkable for its majestic size, dense foliage and magnolia-like flowers.  The trunk rises as high as ninety feet without a single branch, and within it are cavities, sometimes a foot and a half long, which cannot be perceived until the bark is split open.  These cavities contain the camphor in clear crystalline masses, and with it an oil known as camphor oil, that is thought by some to be camphor in an immature form.  But the oil, even when crystallized by artificial means, does not produce such good camphor as that already solidified in the tree.”

“To think,” exclaimed Clara, “of camphor growing in that way!  But how do they get it out, Miss Harson?  Do they cut great holes in the trunk of the tree?”

“No, dear; I have just read to you that the camphor cannot be seen until the bark is split open, and the grand trees have to be cut down.  But to do this is no easy matter.  The hard, close-grained timber requires days of hewing and sawing to get it severed.  The masses of roots are as unyielding as iron, and run twisting through the soil to the distance of sixty yards.  Even at their farthest extremity they are as thick as a man’s thigh.”