80 



CHEMISTRY. 



zoic acid, and of the oil of bitter almonds. By the addition of an 

 atom of oxygen and ah atom of water, it forms benzoic acid. By 

 substituting an atom of hydrogen for an atom of oxygen, benzoic 

 acid is converted into the oil of bitter almonds, or the the hydruret 

 of benzule. This hydruret does not pre-exist in the bitter almonds, 

 but is the result of the reaction of two organic principles contained 

 therein, denominated amygdalin and emulsin, or synaptase, with 

 water. 



Benzule forms a compound with amide called henzamide. 



Cinnamyl, C"H«0% has much analogy with benzule. It is the 

 radical of the oil of cinnamoii^ and of a few other compounds. 



Glyceryl, GgH^, the compound radical of glycerine, the hydrated 

 oxide of glyceryl, which is the base common to many oils and fats. 

 Glycerine will be more fully spoken of under the head of Oils. 



Cetyl, C33M33, an organic radical, which performs precisely the 

 same part in spermaceti that glyceryl does in ordinary fats. 



SECTION II. 



VEGETABLE NON-AZOTIZED SUBSTANCES. 



These embrace Gum, Sugar, Fecula, or Starch, and Lignin ; and, 

 according to Prout, they may be considered as hydrates of carho7i. 



GUM. 



This is a proximate principle, which spontaneously exudes from 

 various trees. It is distinguished from resin by being soluble in 

 water and being insoluble in alcohol. 



Guerin divides the gums into three classes : — 1. -4m5m, of which 

 gum arabic is the type, soluble in cold water. 2. Bassorin, of 

 which tragacanth is the type, which swells into a jelly, but does not 

 dissolve in water. 3. Cerasin, from the gum of the cherry-tree ; 

 insoluble in cold, but soluble in hot water. 



The mucilage of gum arabic differs somewhat from the mucilage 

 of flaxseed : the former is precipitated by the subacetate of lead ; the 

 latter by the neutral acetate, 



Pectine, or the jelly of fruits, seems closely allied to the gums. 

 It forms pectic acid, 



SUGAR. 



This is found in various saccharine natural juices, as of the Sugar 

 Cane, the Maple, the Beet, &c. There are several varieties of 

 sugar. 



Cane sugar, C^^H^gOgg ; prepared from the juice of the sugar-cane 

 by boiling and evaporating ; this constitutes common brawn sugar ; 

 it is refined by dissolving in water, and removing the impurities by 



