322 
THE ART OF REARING 
It has been observed that the leaves distributed 
on the hurdles per ounce of eggs, was 13621bs. 
During the life of the silk-worms, there has been 
carried away from the hurdles in dung, 
lbs. oz. 
In the first age 14 
In the second age ..... 4 8 
In the third age . . . . . 19 8 
In the fourth age 60 0 
In the fifth age ..... 660 0 
Total 745 8 
The excremental substance found in the litter, 
or in the fragments of uneaten leaves, when taken 
off the hurdles, weighed 
First age 
Second age . 
Third age 
Fourth age . 
Fifth age 
lbs. oz. drs. 
0 1 4 
1 3 0 
3 9 4 
18 9 4 
132 O O 
Total 155 7 4 
would be too troublesome to sort so large a quantity perfectly, 
nor is there the same motive to do so. These substances 
being by this time grown large, hard, and woody, are less lia- 
ble to fermentation, although they may accumulate as litter. 
If the laboratories are constantly dry, and well aired, these 
substances will do no mischief, but keep the litter light, and 
allow the air to circulate more freely through it. 
When the silk-worms find any leaves they do not like they 
leave them. There arc some of a hazel dark colour, which 
have fermented slightly; these the worms will eat, if they are 
not quite spoiled, nor could I ever perceive they were the 
worse for it ; from which fact it would appear the fermentation 
had not affected the saccharine or resinous part of the leaf. 
