ALCOHOL 279 



Alcohol is derived directly fro.m fruit sugar, and indi- 

 rectly from starch. The grains, as wheat, rye, corn ; and 

 potatoes, supply starch most economically. The starch in 

 these substances is converted into glucose by heating with 

 very dilute sulphuric acid, or by fermentation with malt. 

 Glucose is further acted upon by yeast containing the Torula, 

 cerevisise, which converts 15 per cent, of glucose into alcohol, 

 and carbonic dioxide. C.H^.Oe = 2 C, H, O H + 2 C O,. 



The weak alcohol resulting is subjected to repeated 

 distillation until sufficiently pure and concentrated. In the 

 natural fermentation of fruit sugar in grape juice, during 

 the formation of wine, the amount of alcohol is self-limited 

 to 15, rarely 20 per cent., since the ferment is killed by an 

 amount of alcohol greater than this. 



Derivation- — The official alcohol is derived from rectified 

 spirit, by maceration, first with anhydrous potassium car- 

 bonate, then freshly fused calcium chloride, and finally by 

 distillation. 



Properties. — A liquid composed of about 92.3 per cent., 

 by weight, or 94.9 per cent., by volume, of ethyl alcohol 

 (C2H5O H), and about 7.7 per cent., by weight, of water (U. 

 S. P.) A transparent, colorless, mobile and volatile liquid, 

 of a characteristic, rather agreeable odor, and a burning 

 taste. Spec. gr. about .820 at 15° C. (59° F.). Miscible 

 with water in all proportions and without any trace of 

 cloudiness. Also miscible with ether or chloroform. It is 

 readily volatile at low temperatures, and boils at 78° C. 

 (172.4° F.). It is inflammable and burns with a blue flame. 



Z>ose.— H. & C, §i.-iii. (30.-90.); Sh. & Sw., 3ii.-iv. 

 (8.-15.); D., 3 i.-ii. (4.-8.). 



PREPARATION. 



Alcohol Dilutum. Diluted Alcohol. (U. S. P.) 



A liquid composed of about 41 per cent., by weight, or about 48.6 

 per cent., by volume, of absolute ethyl alcohol (Cj Hs O H), and about 

 59 per cent, of water. (U. S. P. ) 



Derivation. — Alcohol, 500; distilled water, 500. 



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