302 THE ART OF REARING 
straw or chips. The stoves are, however, better 
for heating the air than the fire-places. 
Whichever of these methods may have been 
adopted in the choice of the size and construction 
of a laboratory, it will be practicable, by the aid. 
of the barometer and the thermometer, to neutra- 
lize or destroy the influence of cold, heat, wind, 
stagnant air, damp or corrupt atmosphere, and. 
the fermentation of the litter even may be pre- 
vented or arrested. 
2. Of the Laboratories of Cultivators. 
In general, the laboratories of the tenants, 
farmers, and common cultivators, have the ap- 
pearance of catacombs. I say, in general, for 
there are some few, who, although they may not 
have all the requisites for rearing silk-worms in 
perfection, yet have care sufficient to preserve the 
worms from any very severe disease. 
I have often found, on entering the rooms in 
which these insects were reared, that they were 
damp, ill-lighted by lamps fed with stinking oil, 
the air corrupt and stagnant to a degree that im- 
peded respiration, disagreeable effluvia disguised 
with aromatics, the wickers too close together, 
covered with fermenting litter, upon which the 
silk-worms were pining. The air was never re- 
