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tubes and hexagonal cells in the vascular system of 

 plants are composed of woody fibre ; and when they 

 are not filled with fluid matter they contain some of 

 the solid materials which formed a constituent part of 

 the fluids belonging to them. 



In the roots, trunk, and branches, the bark, al- 

 burnum, and heartwood, the leaves and flowers ; the 

 great basis of the solid parts is woody fibre. It forms 

 by far the greatest part of the heart wood and bark ; 

 there is less in the alburnum, and still less in the leaves 

 and flowers. The alburnum of the birch contains so 

 much sugar and mucilage, that it is sometimes used 

 in the North of Europe as a substitute for bread. The 

 leaves of the cabbage, broccoli, and seacale, contain 

 much mucilage, a little saccharine matter and a little 

 albumen. From a 1OOO parts of the leaves of com- 

 mon cabbage I obtained 41 parts of mucilage, 24 of 

 sugar, and 8 of albuminous matter. 



In bulbous roots, and sometimes in common 

 roots, a large quantity of starch, albumen, and mucil- 

 age, are often found deposited in the vessels ; and 

 they are most abundant after the sap has ceased to 

 flow : and afford a nourishment for the early shoots 

 made in spring. The potatoe is the bulb that contains 

 the largest quantity of soluble matter in its cells and 

 vessels ; and it is of most importance in its appli- 

 cation as food. Potatoes in general afford from x to 4 

 their weight of dry starch. From 100 parts of the 

 common Kidney potatoes , Dr. Pearson obtained from 

 32 to 28 parts of meal, which contained from 23 to 

 20 of starch and mucilage : and 100 parts of the Af- 



