At the proper time the cocoons are gathered and, if immediately to be used, are plunged into hot water. This not only kills the chrysalids but softens the cocoons as well, so that the outer cases may be removed. The cases removed, the rest of the cocoon is soaked in warm water until the gummy matter is softened and the fibres are free enough to be reeled. In the latter process the ends of a number of cocoons, varying from five to twenty, are caught and loosely twisted into a single strand. The silk thus prepared forms the "raw silk" of commerce. Sometimes a number of strands of raw silk are twisted into a coarse thread, thereby forming "thrown silk." For convenience in handling, both raw and thrown silk are made into large skeins called hanks, and most of the silk product is exported in this form. A given quantity of cocoons yields scarcely more than one-tenth its weight in good raw silk. The remaining part, consisting of broken fibres and cases, is shredded and spun into silk thread of inferior quality. This material, commonly called "husks" or "knubs," forms an important item in silk manufacture, and much of it is exported to Europe and America. [Illustration: SILK PRODUCTION] According to traditions, not wholly trustworthy, eggs of the silk-worm were smuggled to India in the head-dress of a Chinese princess. Thence sericulture slowly made its way westward to Persia, Asia Minor, and the Mediterranean countries. Wild silk, a coarse but strong product, is grown in many of these countries, but mainly in China, where it forms an important export. The Chinese product is commercially known as "tussar" silk. Of the product of raw silk, about thirty-five million pounds, China yields about two-fifths, Japan and Italy each one-fifth. The remainder is grown in the Levant, Spain, and France. Most of the raw silk of China is exported from Shanghai and Canton; that of Japan is shipped mainly from Yokohama. Among European countries Italy is the first producer of raw silk, and France the chief manufacturer. By the operation of a heavy tariff a considerable manufacture of silk textiles has grown up in the United States. New York City and Paterson, N.J., are the chief centres of the industry. The southern part of the United States offers an ideal locality for sericulture. Various attempts at silk-worm breeding have failed from lack of training, but not on account of geographic conditions. =Flax.=--The flax of commerce, the basis of linen cloth, is the bast or inner bark-fibre of an annual plant (_Linum usitalissimum_, _i.e._, most useful fibre), native probably to the Mediterranean basin. It ranks among the oldest known textiles. Bundles of unwrought fibre have been found in the lake dwellings of Switzerland, and linen cloth constituted a part of the sepulture wrappings of the ancient Egyptian dead.