The Story of Silk Part 4

"Why?"

"Because after three or four days they should turn to a light slate color if they are the sort of eggs we want. Those that remain yellow are the unfertilized ones and will be of no use to us; we must discard them."

"And do the eggs always remain slate color until hatched?" questioned Pierre.

"No, they next turn to a dull, brownish slate tint and then the caterpillar comes out. The changes may take place more rapidly than this and the entire process require but a day or two. It all depends on the temperature and the light. Josef knows by long experience just what to do to hurry things along."

As Marie and Pierre glanced at the immaculate white shelves that awaited the newcomers, and realized that for the first time the actual care of the work they had so many times idly watched was upon their young shoulders, it seemed like a dream.

"Now there are many pitfalls which we must be careful to avoid,"

announced Josef. "In the first place we must beware of rats, mice, spiders, ants--even chickens. All of these creatures can work havoc among the caterpillars. Probably you will not need to worry about them very much; certainly not the rats, mice or chickens. Hens and chickens cannot get in here if you are watchful and close the doors. As for the rats and mice, your father has pretty thoroughly exterminated them.

Spiders and ants will find little encouragement in a clean place like this, but we must be on the lookout for them, because one never knows when they will creep into a building. The greatest danger, aside from some epidemic spreading and destroying your crop, lies in feeding your silkworms wrongly. Remember, they must have no wet leaves if we want them to live. You know that already, I guess, or you ought to, for you certainly have gathered enough food for them. Moist leaves will make silkworms ill sooner than almost anything else. So never get leaves that are wet with dew or those that have been rained on. When it looks as if a storm was coming pick a sufficient number of leaves in advance and keep them fresh and cool in the cellar."

"The picking does not trouble us so much as the feeding, Josef. We have never done that. How many times must we feed the worms?"

"At the beginning three times a day; and never forget that the young worms must have the youngest and most tender leaves. Later they will need the tougher ones, with more solid food elements in them, but not at first."

"They are pretty fussy, aren't they, Josef?" laughed Marie. "Lots more particular about their food than we are. Mother makes us eat what is set before us, and never allows us to argue as to whether we like it or not; sometimes it isn't what we'd rather have, either."

"But you manage to live and grow fat on it just the same," grinned the old servant. "Now your silkworms wouldn't. They'd die, and that would be the end of them. Of course some varieties are more robust than others; but they all have to have the same care."

"I didn't know there was more than one kind of silkworm!" exclaimed Marie in surprise.

"Of course there are," Pierre retorted. "Even I knew that. There are lots of kinds, and some make much better silk than others."

"Some give more silk, too," Josef put in. "Their coc.o.o.ns are much larger. The big white worm such as we raise here is one of the most profitable. It has four moultings."

"You mean it changes its skin four times?" Marie said.

"Just that. It's a queer life it has, isn't it?" mused the man. "First there is the tiny egg; then comes the caterpillar with all its moultings and its ravenous appet.i.te--then follows the spinning of the coc.o.o.ns; and the long sleep of the chrysalis, or aurelia, as the slumberer inside the coc.o.o.n is sometimes called. And last of all is the moth that comes out of the coc.o.o.n--when we will let it--and lays hundreds of eggs for future crops of silkworms. What a short, hard-working life it is!"

"They are funny creatures anyway," observed Pierre thoughtfully. "They don't seem to want to do any of the things other animals do. Silkworms never crawl about as most caterpillars would. Shouldn't you think that after they were hatched they would like to see where they were and would go crawling all round the room?"

"You would think so," replied Josef. "But they don't. They seem to have no wish to move. Perhaps they realize that all their strength must be saved for eating and spinning. Now and then, of course, if they do not find food near at hand when they are first hatched they will bestir themselves until they reach it; they move more at this stage than at any other; and yet they would not move then if they were not hungry. Their chief aim in life seems to be to eat. They are no travelers, that's sure. Even when they emerge from the chrysalis into the moth they use their wings very little, only fluttering a short distance when they are mating."

"But suppose, Josef, that one wants to get them somewhere else and they won't go," speculated Marie.

"Oh, it is easy enough to move them. That can be done any time by means of a good tempting mulberry leaf; they will cling to it tight as a leach and you can cart them round wherever you wish."

"When do you suppose our silkworms will first change their skins, Josef?" asked Pierre.

"Moult?"

"Yes. I forgot the word for it."

"That all depends on the temperature of the room and on how fast they develop. Usually with the degree of heat we keep here the first moulting takes place within eight days. You see your silkworms are only about a quarter of an inch long at first, and as they increase in size to about three inches their skin is not elastic enough to accommodate their rapid growth. It simply won't hold them. Suppose you or Marie grew twelve times your natural size in a few short weeks?"

"I'd pity Mother, letting out our clothes!" chuckled Marie.

"They couldn't be let out; the material wouldn't be there," replied Josef. "And it would be the same way with your skin. It wouldn't stretch. You'd have to have a new one. That's what the silkworm does--only it does it several times over. No skin made can cover an animal that is a quarter of an inch long one week and three-quarters of an inch long the next, and so on growing in leaps and bounds until it gets up to three inches and sometimes more. Think of growing at that rate! And the little gourmands are not eating all the time, either, because after they are hatched it is three days before they eat much.

They act stupid, and as if they didn't feel well. But later they make up for their loss of appet.i.te--don't you fret."

Josef smiled grimly.

"By the fourth day they are eating at a furious rate," he went on, "and they keep right on stuffing themselves for five days. When they are about eight days old they have expanded until their skin is so tight that it makes them uncomfortable. It seems to pinch and make them ill.

At any rate they act as if they felt pretty poorly and did not want to eat much more. Their next move is to cast their skins. This takes about three or four minutes and is a strenuous business while it lasts; every bit of the old skin goes--even that from the head, jaws, and feet. The ordeal leaves them weak and exhausted, but they soon cheer up, and are eating again furiously as ever. You can't stop them from eating very long."

"How does the new skin look?" inquired Marie. "Just like the other?"

"Why do you ask such foolish questions, Marie?" grumbled Josef. "Haven't you seen your father's silkworms hundreds of times?"

"I'm ashamed to say I never noticed them very much, Josef," returned the girl. "They seemed such horrid little things that I never was interested in them."

"I don't know much about them either," put in Pierre. "I never expected to be raising them myself. If I had I should have examined them more carefully and asked Father lots of questions. It was such a bother always to be gathering mulberry leaves for them that I came to dislike the thought of a silkworm," confessed the boy. "Ever so many times I had to pick leaves when I wanted to go and play. But now, you see, it is different, because they are our own silkworms and of course we want to learn all we can about them. I wish, Josef, you'd please tell us about their new skins."

Josef glanced up good-naturedly.

"If you really want to know of course I'll tell you," he answered. "The new skin looks just about like the old one, except that it is all loose and wrinkled. You know how you look when you are wearing a new suit that your mother has bought for you to grow to, Pierre. Well, that's the way the silkworm's suit looks on him. It is several sizes too big at first.

But by the end of five days he has filled it all out until he is as uncomfortable in it as he was in his old one, and is ready for another."

"And he peels this one off just the same way?"

"Just the same--hat, coat, and gloves. This, as I have said, is not at all easy, for you must remember that his skin fits very closely all about his jaws as well as over all his sixteen legs. These are arranged in pairs so when he shifts his skin it is equal to peeling off eight pairs of stockings. How would you like that?"

The boy and girl shook their heads.

"These legs are very nicely planned, too," went on Josef. "There are six in front--three pairs--neatly covered with a thick, sh.e.l.ly coating; these fit under the first three rings of the silkworm's body and can be used as hands when he is spinning. Then come the other ten legs, or holders, which have tiny hooks on them and are the climbing legs."

"But I thought the silkworm scarcely moved," objected Marie.

"Oh, it can move when it wants to. When it gets ready to spin its coc.o.o.n it climbs until it finds a place that suits it. In addition to all these legs it has wonderfully strong jaws. I suppose the good Lord bestowed these upon the silkworm because most of its work in life is done with its jaws--both its eating and spinning. In proportion to its size the silkworm has stronger jaws than any other of the small creatures. Underneath these jaws are two very tiny apertures set close together through which the caterpillar draws and unites into one the two strands of silk. This is sometimes called the spinaret. The silk substance, which is really a yellow gum, pa.s.ses through the two long glands that run along each side of the silkworm and are fashioned into a single thread in the spinaret."

"And you say the silkworm goes through the process of changing its skin four times, Josef?"

"Yes, four times. You can always tell when it is going to moult, because it raises its head and remains still in that position as if asleep. When it has grown to the full size of its fourth skin it is ready to spin its coc.o.o.n. This is all very simple when you understand it; and yet strange and wonderful, too. You'll follow the process more easily when your own silkworms begin to grow and you can watch them go through all these different stages."

"I do hope our silkworms will hatch and develop safely," remarked Pierre anxiously.

"You needn't fear, I guess," was the comforting reply. "I have helped your father hatch out thousands of eggs, and we seldom have had a bit of trouble. I shouldn't worry. By to-morrow or the next day I plan we shall have as fine a crop of silkworms as one could wish to see."

"I hope so--for our sakes and for Father's," said Marie softly.

[Ill.u.s.tration]

CHAPTER VI