The time that elapses while the silk-worm is undergoing its changes, varies according to the warmth of the weather, and the quantity of nourishment with which it is supplied; the Chinese, who are very particular on this head, take the greatest pains to supply the little creature with food, as on this they say depends the quantity of silk which the worm will produce. They calculate that the same number of insects, which would, if they had attained their full size, in from twenty-three to twenty-five days, produce twenty-five ounces of silk, would only yield twenty ounces if their growth occupied twenty-eight days, and only ten ounces if forty days. During the first twenty-four hours of the creature's existence, the patient Chinese feeds the objects of his care forty-eight times, or once every half hour, and during the second day and night thirty times, and so on, reducing the number of meals as the worms grow older; the care bestowed on their culture, and the numerous precautions taken to preserve them clean and warm, are curiously expressed in the following extract from on old Chinese work on the subject. "The place where their habitation is built must be retired, free from noisome smells, cattle and all noises; a noisome smell, or the least fright, make great impressions upon so tender a breed; even the barking of dogs and the crowing of cocks are capable of putting them in disorder, when they are newly hatched. "For the purpose of paying them every attention, an affectionate mother is provided for the worms, who is careful to supply their wants; she is called _Isan-mon_, mother of the worms. She takes possession of the chamber, but not till she has washed herself and put on clean clothes, which have not the least ill smell; she must not have eaten any thing immediately before, or have handled any wild succory, the smell of which is very prejudicial to these tender creatures; she must be clothed in a plain habit, without any lining, that she may be more sensible of the warmth of the place, and accordingly increase or lessen the fire, but she must carefully avoid making a smoke or raising a dust, which would be very offensive to these tender creatures, which must be carefully humoured before the first time of casting their slough. Every day is to them a year, and has in a manner the four seasons; the morning is the spring, the middle of the day the summer, the evening the autumn, and the night the winter."