CH. v.] HISTORY OF SILK, ETC. 105 



judicial to the health of the insect than being 

 crowded in one spot. Count Dandolo's laboratory, 

 calculated to hold twenty ounces of eggs of silk- 

 worms, which would ultimately yield about twenty 

 hundred weight of cocoons, was thirty feet wide, 

 seventy-seven feet long, and twelve feet high. 



The time from the hatching of an egg to the cat- 

 erpillar spinning, is nearly five weeks. Tiiis period 

 is subdivided by cultivators into five others, marked 

 by the events of the worm moulting. Count Dan- 

 dolo mentions three species of silkworm ; the first 

 the common one, 39,168 eggs of which weigh an 

 ounce, and which casts its skin four times, hence 

 termed the common silkworm of four casts. Sec- 

 ond, the small silkworm of three casts, 42,620 eggs 

 of which weigh an ounce ; the worms and the co- 

 coons of this sort are three fifths smaller than the 

 preceding. They eat as much as the four-cast 

 worm. Their cocoon is better constructed, the 

 thread finer, and, from an equal v»^eight of cocoons, 

 a greater quantity of silk is yielded by the three- 

 cast silkworm than by the common or four-cast 

 one : besides this advantage, these three-cast silk- 

 worms require four days' less care, by which the 

 accidents and expenses of that period are saved. 

 The mulberry-tree, too, being stripped sooner for 

 these, shoots faster, and is therefore better prepared 

 to resist the approaching cold. For these reasons. 

 Count Dandolo strongly urges the cultivation of 

 this species in preference to that of the four-cast or 

 common worm. There is also a large species of 

 four-cast silkworm. The eggs of these are only 

 one fiftieth more in weight, although the worm is, 

 when at its full size, twice and a half as heavy as 

 the mature common four-cast worm. The only ad- 

 vantage these offer is that 18|- lbs. of mulberry 

 leaves will produce Ij lb. of cocoons, while it re- 

 quires 2O4 lbs. to produce the same quantity of silk 

 from the common silkworm- The disadvantages 



