262 INORGANIC AGENTS 



Alcohol is derived directly from 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 containiug the torula 

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

 and carbonic dioxide. CeHi^Oe = 2 C^ H^ O H + 2 C 0^. 



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 (84 per cent, alcohol, by weight), by maceration, first 

 with anhydrous potassium carbonate, then with freshly 

 fused calcium chloride, and finally by distillation. 



Properties. — ^A liquid composed of about 91 per cent., by 

 weight, or 94 per cent., by volume, of ethyl alcohol (CjH^O 

 H), and about 9 per cent., by weight, of water. A transpa- 

 rent, 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 propor- 

 tions and without any trace of cloudiness. Also miscible 

 with ether or chloroform. It is readily volatile at low tem- 

 peratures, and boils at 78^ C. (172.4^ R). It is inflammable 

 and burns with a blue flame. 



Dose.—R. & C, 5i.-iiL (30.-90.); Sh. & Sw., 3ii.-iv. 

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



PREPARATION. 



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



Synonym.— Sy^iritM^ tenuior, B. P. 



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

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

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



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



