This disease, which at a later period became known as " pebrine " - a name given to it by de Quatrefages, one of its many investigators - had first been noticed in France at Cavaillon in the valley of the Durance near Avignon.
The rearing of worms in small educations under special supervision has been found to be a most effective means of combating pebrine.
Pebrine manifests itself by dark spots in the skin of the larvae; the eggs do not hatch out, or hatch imperfectly; the worms are weak, stunted and unequal in growth, languid in movement, fastidious in feeding; many perish before coming to maturity; if they spin a cocoon it is soft and loose, and moths when developed are feeble and inactive.