I had some old mulberry-trees in my garden. My grandfather had planted them. In the fall I was given a small amount of silkworm eggs, and was advised to hatch them and raise silkworms. These eggs are dark gray and so small that in that amount I received I counted 5,835 of them. They are smaller than the tiniest pin-head. They are quite still; and only when you crush them do they crack.
The eggs had been lying around on my table, and I had almost forgotten all about them.
One day, in the spring, I went into the orchard and noticed the buds swelling on the mulberry-trees, and where the sun beat down, the leaves were out. I thought of the silkworm eggs, and took them apart at home and gave them more room. The majority of the eggs were no longer dark gray, as before, but some were light gray, while others were lighter still, with a milky shade.
The next morning, I looked at the eggs, and saw that some of the worms had hatched out, while other eggs were quite swollen. Evidently they felt in their shells that their food was ripening.
The worms were black and shaggy, and so small that it was hard to see them. I looked at them through a magnifying-glass, and saw that in the eggs they lay curled up in rings, and when they came out they straightened themselves out. I went to the garden for some mulberry leaves; I got about three handfuls of leaves, which I put on my table, and began to fix a place for the worms, as I had been taught to do.
While I was fixing the paper, the worms smelled their food and started to crawl toward it. I pushed it away, and began to entice the worms to a leaf, and they made for it, as dogs make for a piece of meat, crawling after the leaf over the cloth of the table and across pencils, scissors, and papers. Then I cut off a piece of paper, stuck holes through it with a penknife, placed the leaf on top of it, and with the leaf put it down on the worms. The worms crawled through the holes, climbed onto the leaf, and started to eat.
When the other worms hatched out, I again put a piece of paper with a leaf on them, and all crawled through the holes and began to eat. The worms gathered on each leaf and nibbled at it from its edges. Then, when they had eaten everything, they crawled on the paper and looked for more food. Then I put on them new sheets of perforated paper with mulberry leaves upon them, and they crawled over to the new food.
They were lying on my shelf, and when there was no leaf, they climbed about the shelf, and came to its very edge, but they never fell down, even though they are blind. The moment a worm comes to an edge, it lets out a web from its mouth before descending, and then it attaches itself to it and lets itself down; it hangs awhile in the air, and watches, and if it wants to get down farther, it does so, and if not, it pulls itself up by its web.
For days at a time the worms did nothing but eat. I had to give them more and more leaves. When a new leaf was brought, and they transferred themselves to it, they made a noise as though a rain were falling on leaves,—that was when they began to eat the new leaf.
Thus the older worms lived for five days. They had grown very large and began to eat ten times as much as ever. On the fifth day, I knew, they would fall asleep, and waited for that to happen. Toward evening, on the fifth day, one of the older worms stuck to the paper and stopped eating and stirring.
The whole next day I watched it for a long time. I knew that worms moulted several times, because they grew up and found it too close in their old skin, and so put on a new one.
My friend and I watched it by turns. In the evening my friend called out:
“It has begun to undress itself,—come!”
I went up to him, and saw that the worm had stuck with its old skin to the paper, had torn a hole at the mouth, and pushed forth its head, and was wiggling and working to get out, but the old skin held it fast. I watched it for a long time as it wiggled and could not get out, and I wanted to help it. I barely touched it with my nail, but soon saw that I had done something very foolish. Under my nail there was something liquid, and the worm didn’t make it. At first I thought that it was blood, but later I learned that the worm has a liquid mass under its skin, so that the skin may come off easier. With my nail I had disturbed the new skin, for, though the worm crawled out, it soon died.
The other worms I did not touch. All of them came out of their skins in the same manner; only a few didn’t make it, and nearly all came out safely, though they struggled hard for a long time.
After shedding their skins, the worms began to eat more voraciously, and more leaves were devoured. Four days later they again fell asleep, and again crawled out of their skins. A still larger quantity of leaves was now consumed by them, and they were now a quarter of an inch in length. Six days later they fell asleep once more, and once more came out in new skins, and now were very large and fat, and we had barely time to get leaves ready for them.
On the ninth day the oldest worms quit eating entirely and climbed up the shelves and rods. I gathered them in and gave them fresh leaves, but they turned their heads away from them, and continued climbing. Then I remembered that when the worms get ready to roll up into larvæ, they stop eating and climb upward.
I left them alone, and began to watch what they would do.
The eldest worms climbed to the ceiling, scattered about, crawled in all directions, and began to draw out single threads in various directions. I watched one of them. It went into a corner, put forth about six threads each two inches long, hung down from them, bent over in a horseshoe, and began to turn its head and let out a silk web which began to cover it all over. Toward evening it was covered by it as though in a mist; the worm could scarcely be seen. On the following morning the worm could no longer be seen; it was all wrapped in silk, and still it spun out more.
Three days later it finished spinning, and quieted down. Later I learned how much web it had spun in those three days. If the whole web were to be unravelled, it would be more than half a mile in length, seldom less. And if we figure out how many times the worm has to toss its head in these three days in order to let out all the web, it will appear that in these three days the worm tosses its head 300,000 times. Consequently, it makes one turn a second, without stopping. But after the work, when we took down a cocoon and broke them open, we found inside the worms all dried up and white, looking like pieces of wax.
I knew that from these larvæ with their white, waxen bodies would come butterflies; but as I looked at them, I could not believe it. None the less I went to look at them on the twentieth day, to see what had become of them.
On the twentieth day, I knew, there was to be a change. Nothing was to be seen, and I was beginning to think that something was wrong, when suddenly I noticed that the end of one of the cocoons grew dark and moist. I thought that it had probably spoiled, and wanted to throw it away. But then I thought that perhaps it began that way, and so I watched to see what would happen. And, indeed, something began to move at the wet end. For a long time I could not make out what it was. Later there appeared something like a head with whiskers. The whiskers moved. Then I noticed a leg sticking out through the hole, then another, and the legs scrambled to get out of the cocoon. It came out more and more, and I saw a wet butterfly. When all six legs scrambled out, the back jumped out, too, and the butterfly crawled out and stopped. When it dried it was white; it straightened its wings, flew away, circled around, and alighted on the window.
Two days later the butterfly on the window-sill laid eggs in a row, and stuck them fast. The eggs were yellow. Twenty-five butterflies laid eggs. I collected five thousand eggs. The following year I raised more worms, and had more silk spun.