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There are five different substances in the mulberry leaves: 1st, The 

 solid or fibrous substance: 2d, The coloring matter: 3d, Water: 4th, 

 The saccharine substance: 5th, The resinous substance. 



The saccharine matter is that which nourishes the insect, and forms 

 its animal substance. The resinous substance is that which, separat- 

 ing gradually from the leaf, attracted by the animal* organization, 

 fills the two silk vessels. According to the different proportions of 

 the elements v/hich compose the leaf, it follows, that cases may occur, 

 in which a greater weight of leaf may yield less that is useful to the 

 pilkv.'orm, as well for its noui'ishment as with respect to the quantity 

 of silk obtained from the animal. Thus the leaf of the black mulberry 

 (a native of Euroj^e,) produces abundant silk, and strong, but coarse. 

 The leaves of v/hite mulberry trees, in high lands, exposed to cold 

 dry v.'inds, and in a light soil, produce a large quantity of strong silk, 

 of the purest and finest quality. The leaf of the same tree, planted in 

 damp situations, and in a stiff soil, produces less silk, and of a quality 

 less pure and fine; but the chief cause which influences the fineness of 

 the silk, is the degree of temperature in which the silkworm is reared, 

 a?, it is hoped, will be demonstrated in the course of this work. 



According to Dandolo, the leaves of the broad-leaved white mul- 

 berry, are little nutritious. The next has a middle size leaf, thick, 

 and of a dark green color. The best mulberry leaf, of any species, is 

 that which is called the double leaf; it is small, not very succulent, of 

 a dark green color, shining, and contains little water; which may be 

 easily ascertained by drying some of them: the tree produces them in 

 great abundance. 



An old tree produces better leaves than young trees; as the tree 

 grows older the leaves diminish in size. 



The leaf of the wild [seedling] tree, contains the greatestj^roportion 

 of boih the nu'ritivc and silky substances.! This opinion of Dandolo, 

 in favor of the wild mulberry tree in preference to the*grafted tree, as 

 food for silkworms, is thus supported: " I have, says he, ascertained 

 the following facts: 



" 1, That 14^ lbs. of wild mulberry leaves, will produce a pound and 

 a half of cocoons, while 20it lbs. of the leaves of the grafted mulberry, 

 are required to yield the same quantity. 



'< 2. That li lbs. of cocoons, proceeding from silkworms fed on 

 leaves of wild mulberry, give about 14 oz. of very fine silk; whilst 

 generally the same weight of silkworms, fed with leaves of the graft- 

 ed mulberry, only yield eleven or twelve ounces of silk. 



" 3. Tbat the silkworms fed on the wild leaves, are always brisker, 

 and have better appetites. 



The result is, that of taking two trees of equal age and vigor, the 

 grafted tree yields 50 !bs. of leaves, and the wild tree only 30 lbs.; 

 the weight of nutritious substance will be nearly equal in each. '* 



" To this authority may be added that of Mr. Martleroy, an experi- 

 enced cultivator in France, who found that silkworms, fed with tY^^ 



* More correctly, decomposed, and assimilated by the worm. 

 I D&ndolo, cliap. 3. 



