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THE POPULAR SCIENCE MONTHLY 



country, or a philosopher, who had found in some old book forgotten 

 facts, should tell you, " There exists, in a country three or four thou- 

 sand 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 pre- 

 pare 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 op Heather arranged so that the Silk-worm mat 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 co- 

 coons 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 



