THE SILK-WORM. 87 



make use of every moment, and almost continu- 

 ally are eating, except at those intervals when 

 they change their skins. If mulberry leaves 

 be difficult to be obtained, the leaves of lettuce 

 or hollyhock will sustain them ; but they do not 

 thrive so well upon their new diet, and their silk 

 w r ill neither be so copious, nor of so good a quality. 



Though the judicious choice, and careful man- 

 agement of their diet, is absolutely necessary, yet 

 there is another precaution of equal importance, 

 which is to give them air, and open their cham- 

 ber windows, at such times as the sun shines 

 warmest. The place also must be kept as clean 

 as possible, not only the several floors that are 

 laid to receive their ordure, but the whole apart- 

 ments in general. These things well observed, 

 contribute greatly to their health and increase. 



The worm, at the time it bursts the shell, is 

 extremely small and of a black colour, but the 

 head is of a more shining black than the rest of 

 the body ; some days after, they begin to turn 

 whitish, or of an ash-coloured grey. After the 

 skin begins to grow too rigid, or the animal is 

 stinted within it, the insect throws it off and ap- 

 pears clothed anew ; it then becomes larger and 

 much whiter, though it has a greenish cast ; after 

 some days, which are more or less according to 

 the different heat of the climate, or to the quality 

 of the food, it leaves off eating, and seems to sleep 

 for two days together ; then it begins to stir, and 

 put itself into violent motions, till the skin falls 

 off the second time, and is thrown aside by the 

 animal's feet. All these changes are made in 



