578 CONSIDERATION OF CARBON COMPOUNDS. 



Oil of bitter almond, Oleum amyg-dalse amarse. Benzaldehyde 

 does not occur in a free state in nature, but is formed by a peculiar 

 fermentation of a glucoside, amygdalin, existing in bitter almonds, in 

 cherry-laurel, and in the kernels of peaches, cherries, etc., but not in 

 sweet almonds. The ferment causing the decomposition of amygdalin 

 is a substance termed emulsin, which is found in both bitter and 

 sweet almonds. As water is required for the decomposition, the 

 emulsin does not act upon the amygdalin contained in the same seed 

 until water is added, when the decomposition takes place as follows ; 



C 20 H 27 NO n + 2H 2 = 2C 6 H 12 6 -f HCN + C 7 H 6 O. 

 Amygdalin. Water. Glucose. Hydrocyanic Benzaldehyde. 



acid. 



The oil is obtained by maceration of bitter almonds with water, 

 and subsequent distillation when it distils over with hydrocyanic 

 acid and steam, and separates as a heavy oil in the distillate. 



It is an almost colorless, thin liquid of a characteristic aromatic 

 odor, a bitter and burning taste, and a neutral reaction. Pure benz- 

 aldehyde is not poisonous, but the oil of bitter almond is poisonous 

 on account of its containing hydrocyanic acid. 



Sitter-almond water, Aqua amygdalae amarce, is made by dissolving 

 1 part of the oil in 999 parts of water. 



Cinnamic aldehyde, Cinnaldehydum, C 6 H 5 .CH : CH.COH = 131.07 (Arti- 

 ficial oil of cinnamon, Cinnamyl aldehyde, Phenyl acrolein}. This aldehyde is 

 prepared synthetically, or is obtained from oil of cinnamon by extracting with 

 acid sodium sulphite. Cinnamic aldehyde is a colorless oil, having a cinna- 

 mon-like odor and a burning, aromatic taste. When exposed to the air it is 

 oxidized to cinnarnic acid. 



Vanillin, Vanillhmm, C 6 H 3 .OH.OCH 3 .COH. 4:3:1 = 150.92 (Methylpro- 

 tocatechuic aldehyde}. Vanillin is the active constituent in vanilla bean, and is 

 made artificially in a variety of ways. One of these is the action of chloroform 

 and caustic potash on guaiacol. It occurs in white, crystalline needles, having 

 the odor and taste of vanilla, and melting at 80 to 81 C. It is soluble in 100 

 parts of cold and 15 parts of warm water, easily soluble in alcohol, ether, 

 chloroform, and dilute alkalies. It is extracted completely from its solution in 

 ether by shaking with a saturated aqueous solution of sodium bisulphite, from 

 which it may be precipitated by sulphuric acid ; it is also extracted by ammo- 

 nia water. 



,0 CO 



Ooumarin, C 6 H,( the anhydride of ortho-hydroxy-cinnamic 



X CH=CH, 



acid, is found in the Tonka bean and resembles vanillin in odor. It forms 

 white, shining prisms, melting at 67 C., and soluble in 400 parts of cold, 45 

 parts of hot water, and in 7.5 parts of alcohol ; easily soluble in ether. 



An aqueous solution of vanillin is turned blue by a few drops of ferric chlo- 

 ride solution, coumarin is not. An aqueous solution of coumarin, unlike va- 



