CH. v.] HISTORY OF SILK, ETC. 107 



The extent of space which should be occupied by 

 the silkworms in their different ages is no less 

 essential than the due regulation of temperature 

 *o their development; an ounce of eggs should 

 have a space, 



In the first age, of 7 feet 4 inches square ; 

 In the second age, of 14 feet 8 inches square ; 

 In the third age, of 34 feet 6 inches square ; 

 In the fourth age, of 82 feet 6 inches square ; 

 In the fifth age, of 183 feet 4 inches square. 



The food which they consume should be no less 

 accurately determined; and great care must be 

 taken in picking and sorting the leaves for the feed- 

 ing of the worms of the first ages, such as picking 

 off all the twigs, the stalks of the leaves, spots, &c., 

 and to clear them as much as possible from all use- 

 less parts. This operation is most essential in the 

 two first ages, when the leaves are to be chopped 

 very small. In the third age, the sorting and pick- 

 ing the leaves is not of much consequence, and still 

 less so in the fourth and fifth ages. 



The sorting and picking is of importance, inas- 

 much as it enables you to put fifteen or twenty per 

 cent, less substance upon the wickers than would 

 otherwise be done, and which the worms would not 

 eat. This substance increases the litter and the 

 moisture, without necessity or motive. In climates 

 where they are in the open air, it would, of course, 

 be unnecessary to sort the leaves. 



In the fifth, and even in the fourth age, when the 

 season is favourable, leaves, mixed with a quantity 

 of mulberries, boughs and stalks, may be put on the 

 hurdles, although it is known that the worms do not 

 eat them, because at that period it would be too 

 troublesome to sort so large a quantity perfectly, 

 nor is there the same motive to do so. These sub- 

 stances being by this time grown large, hard, and 

 woody, are less liable to fermentation, although 

 they may accumulate as litter. If the laboratories 



