ere the temperature was graded to a higher degree of heat
that the warmer atmosphere might stimulate them to work.

When at last the cocoons were done the Brettons surveyed them with
satisfaction.

The weeks had been busy, fatiguing ones with hastily snatched meals, and
interrupted slumbers.

"One could not keep on like this for a long stretch without more help,"
declared Madame Bretton. "I am glad the caterpillars have their houses
made!"

"They are better houses than you think, too," added Josef. "For each
silkworm has coated the inside of his little home with a gum-like
substance that makes it waterproof. He has no intention of lying down to
sleep in a leaky cottage where the rain may drip through."

"But there is no rain in here," objected Marie.

"Of course not. But the silkworm does not know that. He builds his house
just as he would if it was out-of-doors where the good Lord intended it
should be. Your caterpillar hasn't the wit to realize that conditions
have changed with the years, and that he now lives out his days beneath
a roof that does away with the need of water-proofing. It is because the
cocoons are thus sealed on the inside that the water does not penetrate
them when they are floated. You'll notice that if you ever have a chance
to see the silk reeled off. It protects the chrysalis until it pierces
its way through its silken house and comes out a moth. But of course we
shall not let ours do that."

"Why not?" inquired Marie.

"Why not? Because after you have worked so hard to get your silk you do
not want it broken into short bits and spoiled, do you? If we were to
let the moths mature and make holes in the cocoons it would ruin all our
silk. No. We must let only a few moths come out and lay their eggs that
we may have them to hatch for our next crop of silkworms. We'll select
some of the finest cocoons for the purpose--those that are largest and
most perfect. Some must be male and some must be female moths."

"But how can we tell? Aren't they all shut up inside the cocoons?"
gasped Pierre.

"Oh, it is quite easy," answered Josef. "The female silkworm spins a
house which, like an egg, is a little sharper at one end than at the
other. We'll choose about the same number of each gender. There is a
knack in selecting good cocoons for breeding, and you've got to know
lots of things about them. And after we have chosen them there will be
the rest of the cocoons to sort. That will require care, to