country, or a philosopher, who had found in some old book forgotten facts, should tell you, "There exists, in a country three or four thousand leagues from here, in the south of Asia, a tree and a caterpillar. The tree produces nothing but leaves which nourish the caterpillar." To a certainty, most of you would say at first, "What of it?"
If the traveller or the man of learning should go on to say: "But this caterpillar is good for something; it produces a species of cocoon, which the inhabitants know how to spin, and which they weave into beautiful and durable fabrics. Would you not like to enter upon the manufacture?" You would infallibly reply: "Have we not wool from which to weave our winter vestments, and hemp, flax, and cotton, for our summer clothing? Why should we cultivate this caterpillar and its cocoons?"
But suppose that the traveller or philosopher, insisting, should add: "We should have to acclimate this tree and this caterpillar. The tree, it is true, bears no fruit, and we must plant thousands of them, for their leaves are to nourish the caterpillar, and it is necessary to raise these caterpillars by the millions. To this end we must build houses expressly for them, enlist and pay men to take care of them to feed them, watch them, and gather by hand the leaves on which they live. The rooms where these insects are kept must be warmed and ventilated with the greatest care. Well-paid laborers will prepare and serve their repasts, at regular hours. When the moment arrives for the animal to spin his cocoon, he must have a sort of bower of heather (Fig. 1), or branches of some other kind, properly prepared.
Fig. 1.
Sprigs of Heather arranged so that the Silk-worm may mount into them.
And then, at the last day of its life, we must, with the minutest care and the greatest pains, assure its reproduction. Would you not shrug your shoulders and say, "Who, then, is such a madman as to spend so much care and money to raise—what?—some caterpillars!"
Finally, if your interlocutor should add—"We will gather the cocoons spun by these caterpillars, and then the manufacture which spins them will arise, which will call out all the resources of mechanics. Still another new industry would employ this thread in fabricating stuffs. The value of this thread, of these tissues, would be counted by hundreds of millions for France alone; millions that would benefit
