Mary E. Marcy

The Busy Silk Worm

(October 1911)

The International Socialist Review, Vol. 12 No. 4, October 1911, pp. 222–226.
Transcribed by Matthew Siegfried.
Marked up by Einde O’Callaghan for the Marxists’ Internet Archive.

THE wonderful insect that makes silk is the larva of the mulberry silk-moth of China, commonly called the silk worm. First reared in China, it is now extensively cultivated in China, Japan, Italy, France, Spain and other European countries. Owing to the higher price of labor power in the United States, capitalists cannot here compete with these countries in the production of raw silk They go “abroad.”

The silk industry originated in China and, according to historians, has existed there from a very remote period. The Empress, known as the Lady Si-ling, encouraged the cultivation of the mulberry tree, the rearing of silk worms and the reeling of silk as early as 2640 B.C. She is said to have devoted herself to the care of silk worms and the Chinese credit her with the invention of the loom.

For many years the Chinese guarded the secrets of their art with vigilant jealousy. No one, under pain of death, was allowed to export the silk worm from China. The Emperor Aurelian is said to have refused his empress a silken robe on the ground of its great costliness. Silk was worth its weight in gold.

According to a tradition, the eggs of the silk moth and the seed of the mulberry tree were first carried to India by a Chinese princess concealed in the lining of her head dress.

The silk-moth, so important in the field of manufacture, exists in four states – egg, larva, chrysalis and adult. From the eggs of the moth the tiny worms scarcely an eighth of an inch in length, gnaw their way out.

Small, tender mulberry leaves are fed, the young worm simply piercing and sucking the sap. Soon the worms become large enough to eat the leaves themselves. Their jaws move sidewise and silk culturist report that several thousand worms eating make a noise like falling rain.

Women or girls keep the worms on trays of matting placed on racks. The leaves are placed beside the worms. The worms breathe through spiracles, small holes down each side of the body. They have no eyes but are very sensitive to jarring. The rapid growth of silk worms is marvelous. During the few days prior to its spinning, the worm often grows from one and one-fourth to two inches in length. At all ages the silk worm secretes silk to protect itself from injury. When in danger of falling it instantly fastens a silken thread to whatever it may be standing upon. In case of accident, the worm uses this thread, which is strong enough to sustain its weight, as a ladder to go either up or down. In ascending the thread is wound around its forelegs to shorten it. The thread is always strong enough to sustain the worm.

Upon attaining its full growth, the worm is ready to spin its cocoon. It seeks a quiet corner and moves its head from side to side to find an object to which it may attach its guy lines, within which to build its cocoon. The worm works incessantly, forcing the silk out by the contraction of its body.

The cocoon is tough, strong and compact, composed of a firm, continuous thread. When the worm first begins spinning its work is very rapid. From nine to twelve inches of silk flow from it every minute.

Soon the ten prolegs of the worm disappear and the four wings of the future moth are folded over the breast together with six legs and two feelers. With no jaws, and confined within the narrow space of the cocoon, the moth has difficulty in escaping. After two or three weeks the shell of the chrysalis bursts and the moth ejects against the end of the moistens and dissolves the hard gummy lining. Pushing aside the silken threads, sometimes breaking them, the moth emerges. But the escape of the moth breaks so many threads that the cocoons are spoiled for reeling, so that when the moths are not intended for seed the cocoons are placed in a steam heater to stifle the chrysalis. Then the silk may be reeled at any time.

The moths have no mouths but they do have eyes. From the time the silk worm emerges and reproduces itself in the shape of eggs, the insect eats nothing. Soon after mating the eggs are laid. The moth lays from three to four hundred eggs. It would take thirty thousand of these eggs to weigh one ounce. It takes from twenty-five hundred to three thousand cocoons to make a pound of reeled silk.

Silk is nearly always sent to the United States reeled, ready for the manufacturer. The silk operator brushes aside the silk threads that, fasten the cocoon to the twig and plunges the cocoon into warm water. The end of the silk thread is then found and the cocoon carefully unwound.

The threads of four or more cocoons are gathered together, according to the size thread wanted. These are twisted around each other either by foot or machine power.

Imported raw silk comes in skeins of from one to several ounces, packed into bundles called “books.” In China and Japan the books are usually sold in bales varying from 100 to 160.

It is a fact rarely known that silk is the strongest fibre known to science, as well as the only fibre proof against decay. Cotton will soon mildew and rot away, while silk is in its element when wet and may even be soaked in water without impairing its strength.

Sericulture is interested in rearing silk worms under artificial or what we might call domestic conditions, their feeding and securing cocoons. It is also interested in maturing a sufficient number of moths to supply eggs for the cultivation of the following year. Under domestication the eggs of the silk worm are hatched out by artificial heat when the mulberry leaves are ready for feeding the larvae.

The Bacological Institute of Trent (Austrian Tyrol) was founded for the purpose of making Tyrolese silk culturists independent of imported “seed” or silk worm eggs. The production of some eggs of good breeds is most important.

This institute keeps about 25,000 ounces of eggs through the winter in cold storage in a current of dry air. In April the eggs are shipped to domestic and foreign purchasers to whom they are sold. Each ounce of eggs yields about 160 pounds of cocoons of a very high quality.

When the cocoons are received at the institute, the female cocoons are separated from the males and all cocoons of abnormal appearance are rejected. A few cocoons are brought rapidly to maturity in incubators heated to about 90 degrees F. and the consignment is not accepted unless healthy moths emerge from the sample cocoons. The cocoons are then placed singly in compartments or boxes and allowed to develop normally.

At the season when the moths emerge, 300 women are employed day and night in imprisoning the moths in cells of gauze or waxed paper which are mounted on frames and suspended from the ceiling. The imprisoned moths die after they have laid their eggs. The cells are then opened and the dead moths examined under the microscope.

The eggs produced by the healthy moths are collected from the cells, washed and spread out to dry on frames covered linen. These are used for future seed.

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Last updated on 31 May 2022