SILK-WORMS. 
2G5 
transpiration, and accumulation of the above- 
mentioned substances, take place more commonly 
acid. This phenomenon may occur in some circumstances 
incident to the silk-worm, in which chemical analysis may 
discover acid particles, earthy and alkaline substances, that 
only need an agent, such as an acid, to produce new at- 
tractions, from which proceeds the disease termed calci- 
nation, which is no other than the segno, or spotted disease, 
in which the chemical action is more prevalent. 
“ The quantity of carbonic acid which is discharged by the 
silk-worms is in greater proportion when the worms are nu- 
merous, when the temperature is high in the laboratory, ancl 
when the atmosphere is laden with moisture. This same 
acid is well known to be heavier than the .atmospheric air ; and 
consequently it would fill constantly the regions of pure air 
which are in immediate contact with the silk-worms, if fare 
were not taken to establish currents of air to expel it, which 
may be proved by using the eudiometer. 
“ Carbonic acid may for a time strike on the body of the 
silk- worms without causing death ; because cold-blooded ani- 
mals do not die immediately on being plunged into this gas, 
but chemical attractions may ensue very speedily in the inte- 
rior of the insect, which make it liable to the above-mentioned 
diseases. If all means are not taken to expel this gas, it 
continues to act so forcibly, that it may not be possible to ar- 
rest the progress of the chemical attractions which succes- 
sively occur, until at last the animal is in a state of such de- 
composition, that it becomes a body differing entirely from 
its natural organization. 
“ At the period of its existence when it pours its silk, the 
chemical attractions act most forcibly upon it, and can con- 
vert it instantaneously into an incorruptible compound, as 
is commonly observed.” 
The disease which the Italians term giallnme, or jaundice, 
appears to me to be that which the French call caches, gras 
jaunes ; is caused, according to M. Dandolo, by the action 
of a certain quantity of moisture mixed with carbonic acid. 
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