SILK CULTURE.

Thames Star, Volume VII, Issue 2780, 11 January 1878, Page 3

SILK CULTURE.

By ALEXANDER WaIIiACE, M.D

Reprinted for the Thames Scricultural Association

from "Cassell's Technical Educator."]

Chapter I. (Continued from our last.J

Various Worms producing Silk — Conditions necessary for success in Silk Culture — Life of the Insect: the egg stage. 3. Tho third point of importance is the parity and sanity of the eggs to be operated upon. It is well known that a peculiar disease, "la pebrine," not yet thoroughly understood, has devastated many of the silk - growiufj districts, especially in "Furopo. It is therefore necessary to procure eggs or erain from countries as yet unaffected by the disease. "With this view," large imports of eggs have come from Japan, China, and other parts, and the price of good grain has risen from 5s to 25s per ounce. In 1869 the total value of eggs imported into France alone for home use was aa follows:— Prom Japan, 9,436,000 francs; Egypt, 1,232,000 francs; China, 560,000 francs. The total value of exports of

- eggs of French produce was 3,378,700 i^irancs, being chiefly to Itiily, the proportion of eggs required by Italy to those required by France being about 6 to 2 This shows the great demand for healthy seed from new countries. For the purpose of rearing sound grain, England is considered by French savans to be remarkably adapted by reason of its temperate climate. The Cape, California, New Zealand, and Australia are also especially favored districts. In fact, the disease is eliminated, and quite disappears under proper treatment in the latter country. Mr Charles Brady, of Sydney, N.S.W., writes :—" The mulberry of all varieties thrives here remarkably well, and I have' every reason to believe that its silkworm may, even if severely diseased on introduction, soon become quite sound by proper treatment under our invigorating atmosphere. My experiment!) have been uniformly successfulin regard to eliminating disease." I have myself received from Mr Brady eggs of a celebrated European race (Milanaise), no# very subject in Europe to disease, which have been pronounced, after microscopic examination by skilled experts, to be perfectly free from all sign of disease. It is especially desirable to renovate the old wees of the Bombyx Mobi, which have been ennobled in former generations for the quality of their produce, but which are now nearly exterminated from the prevalence of the disease, by importing their grain into new localities where disease is unknown. Settlers in Australia, New Zealand, and similar localities should especially consider what great pecuniary advantages are offered to them from this branch of sericulture. Another point of great importance, in reference to our Australian Colonies, is mentioned by Mr Brady. " I have had silkworms in all stages *of their development* from the egg to the imagoe, every day in the year, and I am able to feed up several generations in the year, and rear a brood at will at anyseason. Hence we have a remarkable advantage in our climate, in being able to produce many crops a year, or, as it may be otherwise ex-, pressed, to spread the season over a largo portion of the year, thereby gaining manifold what could otherwise be obtained." In Europe the annual worm having one brood; only per annum, produces the mo3fc valuable cocoon. The "bivoltine," or Wofm rHavinK"two generations per annum, is also cultivated, b;ut its \ produce is inferior. *In.hot countries, as India, silkworms having three or' more generations in the year (such as Bombyx Sinenbis, a monthly worm) are cultivated; the cocoon in;these faces, being always smal-' ler^is f deficient in quantity, and generally in quality of produce. The annual worm is therefore most esteemed, and these races, according to Mr Brady, may in Australia be made to produce three crops of silk per-, annum without deterioration of the cocoon. _ This gives a decided advantage to cultivators in that country. The value of the different races of the BombyxMobi, admitting their sanity to be equal, depends on their produce—the cocoon~7i.e., on the amount of rsilk which can be reeled from, a;given number of cocoons, which, should ail possess.more or less the typical points of the race, viz. : the Novi, an Italian race, of which the Moricand is one of the best examples, spins a; large, white, oval cocoon j the Milanaise, another very valuable race, spins a large cocoon, smaller than the Moricand, more elongated, 'of a buff colour; and so on. Japanese races are of different colourswhite, buff, green, &c. —but all possess a peculiar property of being nipped-in in the centre, as if the cocoon had been spun in * two- halves and jbijaed in the centre. Cocoons which feel hard and firm to the touch possess more silk, and are preferred as having a greater value ; thin and. soft cocoons are rejected as inferior. These three main points being secured, viz., a good supply of mulberry-leaves, a suitable magnanerie, and eggs of a healthy race of approved value, let us follow the life of the insect, beginning from the egg stage, to the cocoon; and ~ -examining the manipulation and treatment employed by educateurs in the different stages. 1. The Ego Stage.—The old proverb must be borne in mind, " A good beginning makes a good ending." If deterioration takes place in the egg stage, rigorous, healthy worms cannot be expected; therefore care must be taken even of the eggs. These arc deposited bjfr the moths on paper, cloth, or other suitable material. They should be. kept in a cool, airy room, free from damp, and once a month at least be thoroughly ventilated. The Japanese wrap the enrds on which their eggs are laid in paper bags, and hang them to the roof of their dwellings, which, being made of bamboo, are very freely ventilated. During the egg stage alone races may be transferred from one country to another, and the trade in silkworms-eggs has assumed large proportions. In 1869 two millions of cards, costing on an average 123 6d eaah, were sent to "Europe from Japan. Special steamers are chartered to bring home this valuable cargo as speedily as possible, and during the voyage, in suitable weather, the boxes are opened and the contents ventilated. In each box, which is three feet long, and on which a freight of £3 is paid, are packed 200. cards in separate grooves, so as to allow of ventilation between each card, and to avoid friction. Each card contains about five-sixths of an ounceiof eggs, and costs from three to four dollars in^apan. It is a matter of the greatest importance to export eggs as soon as possible after they have been laid, an.d before tbjOy have been exposed to any

chill from cold weather, especially if they have to travel long distances. Exposure to cold is necessary io set in action vital changes in the eec;. which, once begun, cannot ho stopped with v' d fcrioralion, and a subsequent cl:-nn:-o fn a warmer climate will then hatch out 'he egsj prematurely. This T have proved for several years to be the cn<o with th« egps of Bombtx Mori and Bombyx Yama M"at, and also with the cocoons of Bomisyx Pbumti, CECKoriA, mid olhor rnces The only safe rule is to forward eggs or J cocoons in the autumn as quickly as; possible; ice in any form is dangerous, I and should never be employed. i