112 
THE ART OF REARING 
supplies almost all the animal fluid in them. And 
this it is that, before the surface of the skin they 
are going to cast becomes wrinkled and dry, 
causes them to appear of a yellowish white colour 
like amber, and semi-transparent. 
When the worms prepare for the third, and 
even fourth, moulting, the air of the laboratory 
should be gently agitated, but the temperature 
should not be much varied ; this may be done by 
more or less opening the ventilators in the ceiling, 
and those in the floor, constructed as we shall 
hereafter explain. (Chap. XIII.) 
Sixth Day of the Third Age. 
(Fifteenth of the Rearing- of the Silk-worm.) 
On this day the silk-worms begin to rouse, and 
thus accomplish the third age. 
The general view of this age presents the fol- 
lowing result. 
In six days the silk-worm goes through its 
third age. 
In this age, those worms proceeding from five 
ounces of eggs have consumed nearly 300 pounds 
of leaves and young shoots ; adding to this weight 
45 pounds of refuse and pickings, 345 pounds’ 
weight have been drawn from the tree, or 69 
pounds given to an ounce of eggs. 
The muzzle of the silk-worm, during the third 
age, has maintained a reddish ash-colour, and is 
