Natural history of insects : comprising their architecture, transformations, senses, food, habits--collection, preservation and arrangement . Side view of the Silk-tubc. Section of ike Silk-tuhe, magnifed 22,000 times. You may sometimes have seen, says the Abb^de la Pluche, in the work-rooms of goldsmiths orgold wire-drawers, certain iron plates, pierced withholes of different calibres, through which they drawgold and silver wire, in order to render it finer. Thesilk-worm has under her mouth such a kind of instru-ment, perforated with a pair of holes [united into oneon the outside],* through w
Natural history of insects : comprising their architecture, transformations, senses, food, habits--collection, preservation and arrangement . Side view of the Silk-tubc. Section of ike Silk-tuhe, magnifed 22,000 times. You may sometimes have seen, says the Abb^de la Pluche, in the work-rooms of goldsmiths orgold wire-drawers, certain iron plates, pierced withholes of different calibres, through which they drawgold and silver wire, in order to render it finer. Thesilk-worm has under her mouth such a kind of instru-ment, perforated with a pair of holes [united into oneon the outside],* through which she draws two dropsof the gum that fills her two bags. These instruments * Lyonnet. SPINNING CATERPILLARS, 311. Lahiura or lower Ui^ of Ccssus.— a. Silk-tiil^e. arc like a pair of clistafFs for spinning the gum into asilken thread. She fixes the fxrst drop of gum thatissues where she pleases, and then draws back herhead, or lets herself fall, while the gum continuingto flow, is dravvn out and lengthened into a doublestream. Upon being exposed to the air, it imme-diately loses its fluidity, becomes dry, and acquiresconsistence and strength. She is never deceived inadjusting the dimensions of the [united] apertures,or in calculating the proper thickness of the thread,but invariably makes the strength of it proportion-able to the weight of her body, It would be a very curious thing to know howthe gum which composes the silk is sepaiated anddrawn oflT from the other juices that nourish theanimal. It must be accomplished like the secre-tions formed by glands in the human body. I amtherefore persuaded that the gum-bags of the silk-worm are furnished with a set cf minute glands,which, being impregna
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Keywords: ., bookcentury1800, bookidnaturalhistoryof01bos, booksubjectinsects
