30 



THE CULTURE OF THE MULBERRY SILKWORM. 



Fig. 13.— Worm which died of flacherie, putrefying after 

 death. (Redrawn from Pasteur.) 



these micro-organisms, in the majority of cases, pla} 7 a prominent part 

 in the development of flacherie, it is well to guard against them. 



The principal causes of flacherie are: (1) Eggs being spoiled 

 through careless preservation; (2) hereditary tendency; (3) overfeed- 

 ing of worms; (4) wet, sweating, dewy, and fermented leaf; (5) leaf 

 submerged in water or full of mud; leaf from a new plantation or 

 from a shaded spot, coarse leaf, or change of leaf; (7) lack of ventila- 

 tion; (8) excessive heat; (9) dust; (10) keeping Worms too thick on 

 trays; (11) accidental deaths of worms from injuries, these putrefy- 

 ing, and the ferments thus 

 created bei n g c o m m u ni - 

 Jmk^mk£^ cated to other worms; (12) 

 debility. 



If these causes are 

 avoided, flacherie is not 

 likely to invade a rearing. To prevent contagion eggs should be 

 dipped in a solution of sulphate of copper before being incubated; 

 and in cleaning shelves and nets, wherever a dead worm is seen, 

 powdered sulphate of lime or copper should be applied. 



Unlike the corpuscles of pebrine, the microscopic organisms, which 

 are probably the immediate cause of flacherie, remain alive from one 

 year to another, and the dust of a rearing room ma}^ contain them in 

 considerable quantities and become the means of infection. Hence, in 

 cases of flacherie, immediately after the rearing, the walls, shelves, 

 and all the implements should be washed in a solution of chloride of 

 lime or some other germicide, and the room should be fumigated with 

 sulphur. 



GATTINE. 



The external signs of gattine are indifference to food, torpor, dysen- 

 tery, and emaciation. It attacks the worm in the first ages, and is 

 especially manifested after a molt. Some- 

 times it is associated with flacherie, and, in 

 its incipient stage, is confounded with this 

 disease. Later the worm becomes extra- 

 ordinarily emaciated and sufficiently tran- 

 sparent to be mistaken for a mature larva. 

 The hooks of the prolegs are lengthened 

 out and strongly attach the worm to whatever it touches 

 torpor creeps on and soon ends its life (fig. 14). 



Worms having flacherie or gattine do not always die before mount- 

 ing into the brush, and if the disease has not entirely invaded the 

 organism they may even arrive at spinning. But instead of mounting 

 with the promptness and rapidity of healthy worms, they stop hesi- 

 tatingly at the base of the brush, then begin slowly to mount, stopping 

 on the first little twigs and distending themselves as though asleep, 



Fig 1 1— Worm emaciated by gattine 

 after the fourth molt. (Redrawn 

 from Nenci ) 



Meanwhile 



