THE SILKWOKM-DISEASE. 155 



which digests badly is doomed to perish of flaclierie, 

 or to furnish a chrysalis and a moth the life of which, 

 through the injury produced by organised ferments, 

 is not normally perfected.' 



Thus, as in the case of pebrine, the morbid sym- 

 ptoms of flacker ie are very variable. All depends on 

 the intensity of the evil that is to say, on the abun- 

 dance and the nature of the parasites developed in the 

 intestinal canal, and also on the period in the life of 

 the worm when this fermentation begins to show itself. 

 The most dangerous of all these ferments are those of 

 the family of vibrios. If they exist in the first phases 

 of the life of the worm, it dies quickly and very soon 

 becomes putrid, sometimes resolving itself into an in- 

 fected pus. The disease often manifests itself in a 

 manner particularly distressing and disastrous to the 

 cultivator. The worms have presented the most beau- 

 tiful appearance up to the time of climbing the 

 heather. The mortality has scarcely been two or 

 three per cent., which is nothing ; the moultings have 

 been effected in a perfect manner, when suddenly, 

 some days after the fourth moulting, the worms be- 

 come languid, crawling with difficulty, and hesitating 

 to take the leaves which are thrown upon their 

 hurdles. If some few have mounted on to the heather, 

 they stretch themselves on the twigs, their bodies swollen 

 with food which they cannot digest. Sometimes they 

 remain there motionless till they die, or, falling, remain 



