206 
THE ART OF REARING 
custom of choosing. Time and experience will 
convince those who know their own interest, of 
the inutility of choosing the cocoon. 
If this choice is to be made, the straw-coloured 
cocoon should be preferred, the hardest, particu- 
larly when the two extremities are hard, and the 
web fine ; those that are a little depressed in the 
middle, as if tightened by a ring, or circle, and 
not the largest. 
The small cocoons, peculiarly hard at the ends, 
and a little depressed in the middle, shew that 
the worm had much strength, since it fastened the 
floss firmly, and rounded it well, working the ex- 
tremities thoroughly, which a weak worm could 
not have done. 
Hitherto I have not been able to discover by 
any experiment that the strength shewn by the 
silk-worm in the formation of the cocoon had any 
influence upon the fecundity of the male, or upon 
the quality of the eggs in the female. Cocoons, 
of various tenuity and different shapes, have 
equally afforded me large quantities of well-im- 
pregnated eggs. Healthy silk-worms, perfectly 
mature, of equal weight, have given cocoons that 
varied in weight. 
It is a fact, that the greater quantity of silky 
substance drawn from a healthy silk-worm, than 
that afforded by a worm equally healthy, only de- 
monstrates, that one had accumulated a greater 
abundance of silk in its reservoirs than the other. 
