“An ashy white caterpillar, the size of the little finger, is raised in large numbers for its cocoon, with which silk stuffs are made. It is called the silkworm. In very clean rooms are placed reed screens, on which they put mulberry leaves, and the young caterpillars come from eggs hatched in the house. The mulberry is a large tree cultivated on purpose to nourish these caterpillars; it has no value except for its leaves, the sole food of silkworms. Large tracts are devoted to its cultivation, so precious is the handiwork of the worm. The caterpillars eat the ration of leaves that is frequently renewed on the screens, and from time to time change their skin, according to their rate of growth. Their appetite is such that the clicking of their jaws is like the noise of a shower falling during a calm on the foliage of the trees. It is true that the room contains thousands and thousands of worms. The caterpillar gets its growth in four or five weeks. Then the screens are set with sprigs of heather, on which the worms climb when the time comes for them to spin their cocoons. They settle themselves one by one amid the sprigs and fasten here and there a multitude of very fine threads, so as to make a kind of network which will hold them suspended and serve them as scaffolding for the great work of the cocoon. “The silk thread comes out of the under lip, through a hole called the spinneret. In the body of the caterpillar the silk material is a very thick, sticky liquid, resembling gum. In coming through the opening of the lip, this liquid is drawn out into a thread, which glues itself to the preceding threads and immediately hardens. The silk matter is not entirely contained in the mulberry leaf that the worm eats, any more than is milk in the grass that the cow browses. The caterpillar makes it out of the materials of its food, just as the cow makes milk of the constituents of her forage. Without the caterpillar’s help man could never extract from the mulberry leaves the material for his costliest fabrics. Our most beautiful silk stuffs really take birth in the worm that drivels them into a thread.