HISTORY OP THE SILK-WORM. 21 



degree of heat combined with an equal degree of mois- 

 ture, with but little inconvenience. 



But if a silk-worm be introduced into a jar charged 

 with carbonic acid gas which would cause a bird or any 

 other warm-blooded animal to die instantly, although 

 the worm will soon exhibit signs of suffering, yet it will 

 live from ten to twenty minutes, and, on being with- 

 drawn from the receiver in due time, it will exhibit no 

 signs of injury, but be apparently as healthy as before. 

 The silk-worm will also live for some minutes in water, 

 especially in the early stages of its existence ; it seems 

 indeed to possess the faculty of disengaging vital air 

 from the water, and even when apparently dead, it will 

 revive on being taken out again. But if, instead of be- 

 ing plunged into water or into mephitic air, its eighteen 

 breathing holes be closed up with grease, it dies in- 

 stantly. 



Some have supposed that noise disconcerts them ; 

 but this appears to be a mistake, as has been proved in 

 France, by the Abbe Rosier and M. Thome, who made 

 the experiment of discharging pistols in the apartments 

 where the silk-worms were kept, which they regarded 

 not. Neither are they in the least affected or annoyed 

 by the barking of dogs, or by concerts of music, or the 

 noise and bustle of cities, even while spinning, or when 

 about ascending, preparatory to this last work. Thun- 

 der, indeed, has sometimes the effect of producing a 

 temporary suspension of their labors, while the insect 

 is completely immersed and insulated in its silken cell ; 

 or, at other times, of causing some of the most feeble 

 to fall; but this is rather to be ascribed to the sudden 

 shock or concussion which is produced upon the earth 

 and atmosphere, by a heavy clap of thunder : also to 

 the extreme lassitude and sense of oppression, which 

 the silk-worms must necessarily suffer, filled as they are 

 with a fluid as highly electrical as silk : and to this, 

 being also superadded, an atmosphere, overcharged with 

 the electrical elements, until, by the silent operation of 



