110 
COCOONS OF PURE SILK. 
cocoons of silkworms, who have contrived this 
covering, it may be to escape notice. When the 
worm began its preparation, the leaf was quite 
green and perfect; and she first of all covered it 
with a coating of silk, that extended np the foot¬ 
stalk, and was firmly wrapped round the branch, 
so that the leaf could not fall or be wafted away. 
The silkworm next drew the edges of the leaf 
together, so as to make a case in which to spin 
the cocoon. For a time, the leaf, that wrapped 
round the cocoon, remained green; but by and 
bye, it became brittle, and changed its color 
to a red or brown, and in the end, was carried 
away by the wind and storm of winter.' Nothing 
now remained but the cocoon itself, which hung 
securely by the silk that covered the foot¬ 
stalk, and was wrapped so firmly round the 
branch. 
A great many silken cocoons would be very 
valuable, if the silk could only be wound off 
them. But the gum, this kind of silkworm uses, 
is so hard that nothing can dissolve it; the silk, 
therefore, can only be used by tearing it to pieces, 
and carding it like wool. You can well imagine, 
how such a process must waste and spoil it; and 
what a benefit it would be if something could be 
discovered that would soften the gum without 
destroying the thread. The moth herself is 
