76 
THE ART OF REARING 
it is certain that the more room silk-worms are 
allowed, the better they eat, digest, breathe, per- 
spire, and rest. The spaces I have mentioned are 
sufficient, and present the advantage of facilitating 
the attendance on the silk-worms, and economize 
their food. 
If this preliminary information is necessary, 
it may not be without advantage exactly to know 
what quantity of the mulberry leaf the silk-worm 
.consumes in its four first ages. 
For the quantity of food I fix, I must suppose 
the following circumstances to exist : — 
That the silk-worms are kept until the first 
casting or moulting at 75° of temperature, be- 
tween 73° and 75° until the second moulting; 
between 7 1° and 73° until the third ; and lastly, 
between 68° and 71° till the fourth moulting. 
One of the foundations of the art of rearing 
the silk -worm, is to know and determine the va- 
rious degrees of heat in which, according to their 
ages, the silk-worms are to live; if this precept is 
not rigidly enforced, nothing can be performed 
with exactness*. 
* The writer of an article upon silk-worms inserted in M. 
Rozier’s Course of Agriculture,' Paris edition, 1801, thus ex- 
presses himself relative to the heat suitable to silk-worms. 
“ It cannot be said that silk-worms are injured by any de- 
gree of heat in these climates, however considerable it may 
be. Native of Asia, it must needs be accustomed to heat 
more intense than it can experience in Europe ; but the sud- 
