At intervals of five days after spinning their cocoons specimens were to be opened and the chrysalides examined microscopically for corpuscles.
If the attack comes on a short time before maturity, the worms are able to spin a cocoon of a feeble character, but worms with this disease never change into chrysalides, but always die in the cocoon before transformation can take place.
Common cocoons enclosing chrysalides weigh each from 16 to 50 grains, or say from 300 to 600 of small breeds and from 270 to 300 of large breeds to the lb.
When the cocoons have been gathered the chrysalides they contain are killed either by dry heat or by exposure to steam.
All cocoons stained by the premature death of the chrysalides (chiques), pierced cocoons, and any from other causes rendered unreelable, are put aside for the spun-silk manufacture.