Volume 65: Macarthur-Onslow correspondence, 1846-1929: No. 423
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largest. A chopper for cutting up the leaves, handy baskets for the distribution of food, a thermometer and a hydrometer complete the furniture of a silk rearing shed.
To achieve a successful rearing, it it of the greatest importance to observe most carefully the following points:-
Uniformity in age, size and development of the worms. The proper methods for obtaining this are given in the subjoined table of detailed instructions.
Regularity in Feeding. Keep to the same hours of feeding, and make sure that the food is well and evenly distributed.
Plenty of space must be given on the trays; crowding often produces disease.
Good thorough ventilation, without draughts sweeping over the worms, is necessary, and as much as possible keep the same temperature in the room, from 75o Fahr. in the first ages, down to 61o in the last two ages and during the spinning. Where artificial temperature is not available, a southerly aspect is to be preferred to any other; especially avoid a northerly one, which produces too sudden a change between day and night temperature.
The greatest cleanliness must be observed in the trays; the food and anything used near or for the silk worms. The hands must always be washed before cutting up and distributing the food. The trays must be thoroughly cleaned from time to time, for this purpose put a tray with the convenient size of mesh over the worms, and sprinkle fresh food on. The worms will rise to it through the meshes, when all are through, lift the two net trays, and throw away the litter in the sackcloth trays underneath, replace it and the fresh tray over, keeping the lower net tray for the next cleaning. The cleaning is best done in the morning, the worms are hungry then and rise quickly. The proper days for cleaning are indicated in the full directions below.
The life of the silk worm, as a worm or larva, is divided into five so-called ages. The ages are, on an average, six days long; during the first four days the worms' appetites increase perceptibly as does the growth. After that time the worm gets languid and finally motionless, having attached the hind part of its body to a leaf or the net by a few silk threads; the head is raised (see illustration 4) and the worm remains in that position for from twenty-four, thirty-six, or even forty-eight hours. Then it crawls by a series of vermicular movements out of its old skin, being provided for the next age's growth with a much wider new skin.