SILK-WORMS. 
257 
But in the ordinary manner of rearing silk- 
worms, the diseases of the silk-worms occur, — 
1. When they lay so thick on the wickers 
that they cannot feed with ease, when they are 
inclined to do so, — as for example, if on a space 
which might contain 10,000 worms, 10,000 more 
are placed, it must be evident, that in this 
case many insects will feed ill, or not at 
all; a difference tin their developement will 
result, and large healthy worms will be found 
mixed with small and sickly worms. This differ- 
ence, which becomes more palpable as the cause 
of it is prolonged, engenders disease, and pro- 
duces death in a great number. 
2. When the custom of keeping the worms 
too thick is in any degree general in an establish- 
ment, the inequality of size in worms is not the 
only ill effect : it will affect the period of their 
transition some silk-worms will be found roused, 
some torpid, and others still requiring food, pre- 
vious to their transition. 
This confusion kills great numbers, even of the 
strongest ; I call those the strongest in the differ- 
ent ages, and particularly in the two first ages, 
that have eaten most, and have soonest sunk into 
torpor. To feed those that still require food, 
and are not torpid, leaves are heaped on the 
litter, which is already damp. The torpid worms 
are buried between the old and the fresh litter, 
