The domestic treatment of the silk-worm hal been brought to great perfection in Italy. For merly the eggs were hatched at uncertain periods depending on the natural warmth of the season or they were put in manure-beds, or were worn in little bags about the person next the skin They are now hatched in an apartment he,ated tc the proper degree by a stove ; but they are firsi washed in water, and afterwards in wine, tc separate light eggs, as well as dirt, and the gummy envelope which surrounds the heavy ones. The temperature of the hatching-room is at first 64°. but is gradually raised 1 or 2 degrees daily, unti it reaches 82°, which it is not to exceed. PieceE of coalse muslin, or of white paper pierced with holes, are placed over themggs when' they are about to lie hatchecl„--"ilirough these the worm creep to tMritip-er surface, and are removed aE SO9P- -aslossible to a cooler place. Young leaveE dud sprigs of mulberry are laid upon the muslin or paper, when the worms eagerly settle on thE leaves, and can thus be transferred to trays, and removed to the nursery. This is a dry room oi regulated warmth, with windows on both sides, so that free ventilation may be attainable. Chlor. ide of lime should be in use to purify the air and a thermometer and hygrometer to regulate the heat and moisture ; the latter is apt to abound where silk-worms are kept, and is very prejudicia to them. Moist exhalations arise from the leaveE and from their bodies. Fermentation, also, soor takes place if litter and dung be not speedily removed from their trays ; these are fertile sourceE of disease among the worms, and may carry ofl thousands in a day. 80 lbs. French (=88 lbs English) of cocoons are the average produce from one ounce of eggs.
Diseases.—One of those to which silk - wormi are liable consists of the forrnation of a minute cryptogamous plant of mildew within the body of the living insect. Damp and fermenting food and litter produce, in the first place, among the fatty matter of the body of the caterpillar, an infinite nurnber of sporules supported by minute stems. These increase to such a degree that the vegetation soon pierces the skin gives a general mealy appearance to the body of the caterpillar, ripens its seed, which is borne by the winds tc every part of the nursery, carrying contagion with it, and at length causes the death of the worms. The dead bodies of worms or moths (for the insect is infected in all stages) are sources of contagion, unless immediately destroyed. This. disease is called museardine in France, calcinettc in Italy. The French name arises from the resemblance of the diseased caterpillar to a mealy kind of sugar-plum made in Provence, and sold by the name of muscardine ; the Italian name also refers to the chalky or mealy surface of the skin. Various fumigations and washes have been tried, in order to purify infecte'd nurseries, and to preserve others from the ravages of this malady ; a solution of blue vitriol, the sulphate of copper applied to the wood-work, frames, et,c., of the nursery, is of great use in destro-ying the seeds of the fungus, but nothing is so good a preservative as rigid attention to cleanliness and good ventila tion. The improved means, first employed in
Italy, for preserving the health of these valuable insects, are due to Count Dandolo, who gave particular and scientific attention to the subject, and superseded many an absurd custom in the rearing of silk-worms. According to his method, wicker shelves are arranged in a room at con venient distances, and are lined with paper on which the worms are placed. Such worms only are placed together as have been hatched at the same time, the space allowed them being, for each ounce of egg, 8 square feet during the first age, 15 feet for the second age, 35 feet for the third age, 82i feet for the fourth, and about 200 feet for the fifth age. The mulberry leaves are chopped, in order to present a large number of fresh-cut edges to the young insect. Four meals a-clay, as a regular:rule, and luncheons between when the ,yvorn4s are particularly voracious, is the liberal allowance for their subsistence. The temperature at which silk-worms are:healthiest appears to be from 68° to 75°, though they are able to bear a much higher temperature. Alternations of heat and cold are exceedingly injurious to them.
The muscardine disease is produced by Botrytis Bassiana ; the still more terrible pebrine disease is caused by a minute vibrio-like organism.
In Madagascar, there is said to be an indigenous silk-worm of great size, fed in the open fields on tlae pigeon-pea (Ambira vatry), and yielding very large cocoons. Little attention, however, is paid to it by the natives. This is probably the silk of which Mr. Consul Pakenham writes, llth August 1869, There is another silk in Madagascar much. esteemed on account of its streng,th, which is said to be collected in a state of floss in the interior, and afterwards treated much the same as cotton.' Mr. Pakenham states that M. de Lastelle imported Bombyx eggs from China, introduced the mulberry, and set up a regular establishment at Tamatavc, which produced several thousand pounds of fine silk.—Von Mueller ; Four 1?eports on Japan Silk, by F. O. Adams, 1870-1871; Mr. C0718111 J. Troup's TOUT in Japan, 1870 ; China Imperial Customs Silk Report, 1881 ; Ure's Dictionary ; Trade Accounts, Statistical Abstract, and Accounts of Trade of Great Britain and British India ; 1Vild Silks of India, b,y Thomas Wardie, 1880; Collection of Papers regarding Tasar Silk, 1879 ; IVin. C. Wyckoj; The Silk Goods of America, 1879 ; Villianis' Middle Kingdom ; Sir J. Sheil, in MarA: ham's Embassy ; Royle's Ai'ts and Manufactures and Productive Resources of India, p. 497 ; Morri son's Compendious Description ; Geoghegan, Silk in India, Calcutta, 1872 ; Capt. Hutton ; Dr. Hors field and Mr. Moore's Lepidopterous Insects ; Harris' Nat. Hist. of the Bible ; Chinese Repository ; Juries' Reports and Catalogues of Exhibitions ; Davies' Chinese ; Fortune's Residence ; Tennent's Ceylon ; Dr. Walker in Madras J. Lit. and Science ; Yule's Cathay ; Hue's Chinese Empire ; Poivell's Handbook.