SILK-WORMS. 
129 
3d. The damp hot nature of the atmospheric 
air, as well as the smothering heat of the labora- 
tory, during the fifth age. 
These evils injure the silk-worm in three ways 
1. The moist exhalations, produced by the 
leaves and the transpiration of the insect, accu- 
mulate in the laboratory, and tend to relax the 
skin of the silk-worm ; this organ thus loses its 
elasticity, puts the animal into a state of languor, 
decreases its appetite, alters its secretions, and 
makes it liable to various diseases, and even to 
death. (Chap. XII.) 
2. The mephitical emanations disengaged from 
the body of the insect, and from the leaves, render 
the silk-worm’s breathing difficult, destroy its ex- 
citability even, produce disease and destruction. 
3. The dampness and stagnation of atmospheric 
air, increased by the moisture of the laboratory, 
create a great fermentation in the dung, and, 
consequently, disengagement of heat, which, by 
destroying the elasticity of the air, renders it so 
deadly, as, in the course of a few hours, to destroy 
the silk-worms entirely *. 
* There is another cause of disease and death, which the 
author does not mention, but which may be found described 
minutely in the Cours d' Agriculture, by M. l'Abbe Itozier, 
and which runs as follows: — 
“ Mephitical air is not the only cause of the speedy death 
of silk-worms. Atmospherical electricity equally contri- 
butes to their destruction, in the manner that it turns milk 
G 5 
