492 EUROPEAN AGRICULTURE. 



ten or twelve per cent., and others eighteen per cent, of silk. 

 The great division of races is, into those which produce a white, 

 and those which produce a yellow, cocoon. It is said that dif 

 ferent races of the worm are suited to different climates, either 

 hot or temperate : and the results are always more or less affected 

 by the mode of feeding and the care bestowed upon them. 



The principal of the white races of worms is called the Sina, 

 and this species produces a very fine and beautiful silk. This 

 species was imported from China almost a century since ; and its 

 excellence has been maintained, and indeed it is represented to 

 be much improved by care and selection. The silk of this 

 species of worm is employed for making the very finest of the 

 white silk fabrics. Ten to twelve pounds of the cocoons produce 

 one pound of silk. The cocoons are cylindrical, round at the 

 ends, with a depression or cincture round the middle. 



The principal of the yellow races is the Turin. This is 

 known in Italy by several different names. The form of the 

 cocoon is cylindrical, with a deep indenture or cincture round 

 the middle ; the ends are round, and the color is a beautiful 

 yellow. They are esteemed as among the best cocoons known, 

 and furnish a very strong silk. 



The Cora is another celebrated race, which is reported to have 

 been the result of a cross between two of the most beautiful and 

 rich of the yellow races, the Turin and the Loudun. This 

 species yields a large return of silk in proportion to the weight 

 of the cocoons ; the cocoons are much sought after, and sell at a 

 higher price than any of the common kinds. As my limits allow 

 me only to refer to the best kinds, I shall not enumerate others, 

 of which there are several sorts, more or less esteemed in differ 

 ent localities. 



The ordinary life of a silk- worm embraces five as:es, or lour 

 important changes. There is a species called the three-change 

 worms ; but this peculiarity is considered as the result of a dis 

 eased constitution, and the product is comparatively worthless. 

 The worms, by extraordinary feeding, may be forced to finish 

 their feeding in some cases in eighteen days ; but this at the 

 expense of a great deal of trouble, and generally at the risk of 

 disease. Their feeding is in some cases extended to fifty days : 

 but this is always owing to scanty and illiberal feeding, and the 

 product is sure to be inferior. The period most to be desired, in 



