BIOLOGY APPLIED TO HEALTHFUL LIVING 541 



potatoes, are commonly used in producing alcoholic liquors, 

 of which the chief varieties are mentioned below. 



Malt liquors (beer, ale, and porter) are made from malt, 

 which is generally sprouted barley grains. This is ground in 

 water, and allowed to ferment. Hops are added to give a 

 bitter flavor. Such a fermented liquor consists chiefly of 

 water, 1 to 8 per cent alcohol, and small quantities of other 

 substances derived from the grains used. 



Wines are juices of grapes which have fermented and pro- 

 duced 6 to 12 per cent of alcohol. Some wines are stronger 

 because brandy or strong alcohol has been added when 

 bottling. 



Distilled liquors (whisky, gin, brandy, rum) contain 30 

 to 50 per cent alcohol, and are made thus strong by distilling 

 the fermented fluids (water with rye, corn, oats, or potatoes 

 for gin and whisky ; molasses in water for rum ; wines for 

 brandy) . Various flavoring and coloring materials are added 

 to the distilled liquors. They differ essentially only in 

 color, flavor, and proportions of alcohol. Some of the sub- 

 stances used to color and flavor are harmful, but are used in 

 such small quantities that the alcohol is chiefly responsible 

 for the physiological injury done by the distilled liquors. 



Alcohol in a more or less pure state can be made by re- 

 distilling and otherwise purifying any fluid in which fermen- 

 tation has occurred. Since distilled liquors are nearly half 

 alcohol, it is easily obtained from them. The grain alcohol 

 of commerce is usually from 91 to 95 per cent pure ; i.e., it 

 contains 5 to 9 per cent of water. A special quality for 

 scientific purposes is about 99 per cent pure, and is very ex- 

 pensive to make. 



Commercial alcohol is usually called " grain-alcohol," or, 

 in chemical terms, ethyl alcohol. Wood-alcohol, or methyl 

 alcohol, is commonly made from wood. In all the discussions 

 in this lesson, the word " alcohol " is used to mean grain or 

 ethyl alcohol, for this is the characteristic constituent of 



