S04 THE PHILOSOPHY 



figure Is generally oval, which necefiarily refults from that 

 of the aivnal's body upon which they are moulded. When 

 fpinning, iliey twifl their bodies into the form of an S. The 

 cod is produced by numberlefs circumvolutions and zigzags 

 of the fame thread. The filk is fpun by an inftrument fitua- 

 ted near the mouth of the infe6^. The filky matter, before 

 it is manufactured by the fpinning inftrument, appears under 

 the form of a gum almoft liquid, which is contained in two 

 large refervoirs comtorted like the inteftines of larger ani- 

 mals, and which terminate at the fpinning inftrument by two 

 parallel and flender conduits. Each conduit furnifhes mat- 

 ter for one thread. The fpinning inftrument, as is evident 

 when viewed by the microfcope, unites the two threads in- 

 to one. Thus a thread of filk, which has the appearance of 

 being iingle, is in reality double, and fpun with great dexteri- 

 ty. Some writers, who delight in the marvellous, afcribe 

 forefight to the filk-worm in fpinning its cod. The lilk- 

 worm, it muft be acknowledged, a(fts as if it forefaw the ap- 

 proaching event. But the truth is, that, when the animal 

 has acquired its full growth, its refervoirs of filk are com- 

 pletely tilled. It then feems to be ftrongly ftimulated to 

 evacuate this glutinous matter. Its different movements and 

 attitudes, while difcharging the filk, produce thofe oval bun- 

 dles which clothe and ornament vaft numbers of the human 

 fpecies. 



Another fpecies of caterpillar conftru£ls its cod in the 

 form of a boat with the keel uppermoft ; but it confifts not 

 entirely of pure filk. The animal, with its teeth, detaches 

 fmall triangular pieces of bark from a bufh or a tree. Thefe 

 pieces of bark it paftes upon its body by means of a gluti- 

 nous or filky fubftance, and they conftitute a principal part 

 of Its cod. 



Another fpecies works alfo in wood, though not with equal 

 art as the former. Its cod is compofed entirely of fmall ir-- 



