Rearing of fVorms.—The mountainous districts at a distance from the sea. appear to be most favourable for the production of the eggs, and the Japanese rearers obtain their seed from Shinshiu. In Japan, the houses for rearing silk-worms are two-storeyed, the corner posts are of wood, the intervals be tween the posts of trellised bamboo covered with an inner and outer coating of dried mnd. The teinperature within is kept at 70° Fahr. The hatching season varies from the 20th April to the 5th May. 13ranclies of the mulberry trees are cut and dried, and in bundles brought to the rearing liouse. To facilitate cleaning the tmys, nets stretched on very light fmmes are laid over the worms, and fresh leaves are spread upon the nets ; the worms, attracted by the fresh leaves, climb up to the nets, and they are then transferred to another set of trays. On the worms ceasing to eat and their skin assuming a transparent colour, they are removed to spin their cocoons to separate trays, called Mabuslii.
The worms and the chrysalides are subject to several diseases. Ono of these, chiefly in the low damp localities, is the attacks of the uji, also called koro and bo, in Chinese or tseu. It is supposed to be inserted into the caterpillar, but does not affect its health until after it has turned into a chrysalis. During the period which follows the formation of tho cocoons, this maggot kills the chrysalis, on the aubstance of which it has been feeding ; and, having attained its full development, it pierces the cocoon. and renders it useless for anything but floss silk. After the uji has left the cocoon, its colour changes from pale-yellow t,o reddish-brown, gradually becoming darker and darker, and after three or four days it is nearly black. It is annulated, without feet, and some times nearly as large as the chrysalis itself. The uji chrysalis becomes a fly.
Mr. F. O. Adams, RM. consul in Japan, writ ing in 1869, and repeating in 1871, says that in the most favoured district in Shiushiu tho propor tion of uji was from 30 to 40 per cent. Near Koshiu it was 56 per cent., besides 10 per cent. of dead chrysalides. In Musashi, Joshiu, and Koshiu, the general proportion was from 60 to 70 per cent., and in one district of Koshiu it even reached 84 per cent. In 1868 the average is said to have been only 10 to 25 per cent.
When the cocoons are retained for eggs, they are placed in a single layer on the feeding trays, and are covered with sheets of paper pierced with holes at regular intervals of two or three inches. After a fortnight, the moths begin to emerge from the cocoon, and, instinctively seeking air and light, they soon pass through the openings in the paper, and couple on its surface, and in tho evening the females are placed on cards, where they lay their eggs, till the following morning. From 50 to 100 female moths are put on a card, which in places is set in a varnished frame, to compel the moth to lay its eggs on the cards', as they dislike varnish.
When the cards are filled, they are bung up in dry, shady places, till the eggs, which are yellow at first, assume the yellow or green hue peculiar to the Japanese produce.
When the cocoon is kept for reeling, the chry salis is killed by exposing the cocoons for several days to the sun, or in the absence of sunshine, to the heat of a charcoal fire. The reeling is per formed by young women, who throw the cocoons into a hot-water basin, and detach from the cluster of threads, four, five, or more, according to the intended thickness of the silk, making them glide over the smooth surface of a thin round rod placed across the basin. It is re-reeled into a larger skein before it is made up into hanks or bundles and offered for sale.
In 1869, 319,829 lbs. avoirdupois of eggs were exported from Japan to France and Italy. The eggs of Bombyx mori and other species of Bombyx, are imported into Europe from Japan at about 25s. the ounce, to supply the deficiency caused by the pebrine disease.
In Bengal, tho system of growing the mulberry as a standard tree has been tried, but with as little success as attended the experiment of the St. Helena variety on the Bombay side of India. The common bush mulberry is very much preferred by tho people at Surdali, connuercially, Radnagore, and all other parts of Bengal, where silk cultiva tion prevails. Tho Mortis alba is infinitely to be preferred as food for the worms of the Bombyx mori, and this has been introduced from China into Europe as well as into India. Morns tho species most common in Bengal, is thought by Dr. Wallich to be only one of its varieties. Moms atro purpurea is a species introduced into India from China, where it is employed as food for the silk worm, though Dr. Roxburgh states that it had not been found to answer for that purpose in Bengal. Two varieties (one, the Doppa foglia) of the Italian white mulberry, received from St. Helena, were established in the East India Company's botanic garden at Dapuri, in the Bombay Presidency. The then superintendent, Dr. Lush, forwarded to Calcutta young plants, which, in September 1833, were reported by Dr. Wallich to be in a, flourish ing condition. Two other species are common in the plains of N.W. India, and others have been introduced there from Kabul and Kashmir ; one distinct species occurs, moreover, in the Himalaya. Colonel Sykes also drew attention to the great importance of introducing into India the mulberry called Morns multicaulis, a distinct species or variety introduced by M. Perrottet into France in 1821, from the Philippine Islands, where it had been brought from China. It is now thought by many, both in Italy and France, to be the most valuable sort for cultivation, and has become a favourite variety in America. Besides growing easily, and affording abundance of leaves of the most nourishing kind, it is said to be able to with stand a considerable degree of cold.