14-6 DISEASES OF SILKWORMS. 



of disease in silkworms ; but of these damp seems to, 

 be the most prejudicial, as will be seen by the fol- 

 lowing experiments : " If a silkworm/' says DJ 

 Lardner, " is introduced into a receiver charged 

 with carbonic acid gas, and in which a bird would 

 instantly die, although the worm quickly exhibit* 

 signs of uneasiness and suffering, it will live for ten. 

 fifteen, or perhaps twenty minutes. No warm- 

 blooded animal could continue alive in such an at- 

 mosphere for half that time. If, after remaining 

 few minutes, the worm be withdrawn from the re- 

 ceiver, it will not exhibit any sign of injury, but 

 will be apparently as healthy as before inhaling 

 this pernicious gas. The silkworm appears enduec 

 with the power to seize upon the minutest portion 

 of vital air which may be held by water, as it will 

 live for some minutes immersed in this fluid, par- 

 ticularly in its first ages ; and, even when seemingly 

 dead, it will revive if taken out. It would seem, 

 however, that when its power of breathing is ob- 

 structed, the worm instantly dies. If, instead o: 

 plunging it in carbonic acid gas, or in water, its 

 eighteen breathing holes are sealed up with grease, 

 it expires instantaneously. 



" If a healthy silkworm be confined in a vessel/ 

 the air in which is charged with moisture, and 

 heated to the temperature of 80 to 90, it will 

 very soon exhibit symptoms of indisposition, and 

 reject food ; the skin will slacken, and the muscles 



