While it remains in the state of a caterpillar, the Silk-worm changes its coat four times, and previous to each moult refuses its food, and appears in a very sickly condition. As soon as its nest or cocoon is finished, and it has changed into the pupa-state, the cocoons are carefully removed from the place where the animal had formed them; and after those which it is intended to keep, that they may perfect their changes and lay eggs for the ensuing year, are removed, the remainder are placed in large vessels, each covered with a thick blanket; they are then exposed to heat sufficiently powerful to destroy the life of the pupæ. This is generally accomplished by placing the vessels in an oven, heated to about the same degree as that of a baker after his loaves are drawn; here they are suffered to remain for about an hour, they are then withdrawn, but the blanket that covers them, is not removed for the space of five or six hours. The first process in preparing the silk, is winding it off the cocoons: for this purpose, after the rough outsides are removed, several handfuls at a time are thrown into a vessel containing water, and placed over a gentle fire, the water is then allowed to be heated to nearly the boiling point; a short stunted brush formed of heath or any other shrub of that description, is now gently moved about among the cocoons, and on withdrawing it from the water, the ends of the silk are found to have adhered to it in several places; the winder then gathers together with her fingers, as many ends as she intends the first description of thread to consist of, and hands them to an assistant, whose office it is to turn the reel as soon as the silk is laid upon it; the principal workwoman, in the mean time, continually adds to the thread the ends of fresh cocoons, as soon as the first are exhausted. The silk, when reeled off in this manner, is called _singles_, and is used in weaving to form the _weft_, that is, the thread that crosses the cloth from side to side. Another description of silk threads, are called trams, and these consist of two or three _singles_ twisted together; but the strongest and most valuable sort is the _organzine_, which is formed by placing skeins of _singles_ upon a reel, and as they are wound off, they are, by the assistance of machinery, strongly twisted. Two or three of these are then taken, and the whole again twisted together to form a stronger thread; this thread is the _organzine_, and is used for the warp or length of the cloth.