] 16 
THE ART OF REARING 
the air would soon be not only moist but pes- 
tilential. (Chap. XII.) 
As we before said, the silk-worms should not 
be lifted off the hurdles, after they have com- 
pleted their third age, until they are nearly all 
well roused, because, should the first-roused have 
to wait a day, or a day and a half, it will not 
hurt them. Those early-roused should be put 
in the coolest part of the laboratory, and the 
late-roused worms in the warmest part. If this 
should be troublesome, it may suffice to give the 
latest-roused worms more space by keeping them 
farther asunder, and they will soon come up to 
the others. 
It is easy to tell by the thermometer which are 
constantly the hottest parts of the laboratory. 
And this knowledge will serve to render all the 
silk-worms even-sized, particularly if those who 
attend them have any practical skill. All this 
care is indispensable, if the worms are required to 
draw their silk equally, and at the same period, 
particularly as there accrue great evils, which I 
shall hereafter demonstrate, when some of the 
silk worms rise too much above the others. (Chap. 
VIII. § 5.) 
It is after the third moulting that the silk- 
worms should be moved into the large laboratory, 
in which they are to remain until the end. The 
