EFFECTS OF ALCOHOL. 109 



at once begins to " worK," that is, it begins to change 

 the sugar to carbonic acid gas and alcohol. Thus 

 wine is made from grapes, currants and other fruits. 

 This kind of fermentation is called vinous fermenta- 

 tion. 



If the process of fermentation is allowed 

 Fermentation ^ con tinue, the hard cider and the fer- 

 mented wine will again change their 

 nature. If a barrel containing cider is left in 

 the warm sun, with an open bung (why), it first 

 changes its sugar into alcohol. Additional ferment 

 will change the alcohol of the hard cider to acetic 

 acid, or cider-vinegar. This is called acetous fer- 

 mentation. 



Beer brewers add water to barley, 

 >m 



IJarley. 



and keep it sufficiently warm to cause 



it to sprout, when the starch it contains 

 will change to sugar. More heat is added, and the 

 germs or young sprouts are killed, and the water 

 evaporated. This is now called malt, which is 

 soaked in water, the sugar which it contains is dis- 

 solved and the sweet liquid drained off. Yeast is 

 added to this liquid, to start the process of fermen- 

 tation, or change of sugar to carbonic acid gas and 

 alcohol. It is now called beer. 



If a cold cup be inverted and held 



Distillation. 



over the spout of a tea-kettle from 

 which steam is escaping, the steam will be condensed 

 and gather in drops on the inner surface of the cup. 



