92 Life and Health 



But when fruit is crushed and its juice pressed out, the 

 minute germs, or micro-organisms, are carried into it, where 

 they absorb the sugar, which is for them as well as for man 

 a source of energy. By so doing they cause a breaking up 

 of the sugar and a rearrangement of its atoms. 



Two new substances result from this decomposition of 

 sugar ; viz., carbon dioxide, which escapes as bubbles of gas 

 into the surrounding air, and alcohol, which remains in the 

 fluid. Now we must remember that fermentation entirely 

 changes the nature of the substance fermented. This law holds 

 good for all forms of decomposition. Before alcoholic fer- 

 mentation the fruit juice was wholesome and beneficial ; 

 after fermentation it contains a liquid commonly known as 

 alcohol, which changes the previously wholesome fruit juice 

 into an intoxicating beverage. 



Experiment 29. To illustrate yeast fermentation. Dissolve one- 

 fourth of a compressed yeast cake in half a cup of warm water ; stir 

 well. Now add two tablespoonfuls of molasses to a pint of warm 

 water. Pour the first mixture into the second and shake well. Place 

 mixture in a wide-mouthed, loosely stoppered quart bottle or quart 

 glass. Note color of the mixture, its taste and smell. 



Place the mixture on shelf near the kitchen fire or in any place 

 where temperature is from 70 to 95 Fahr. After several hours, watch 

 for evidence that the yeast is "working." Note the bubbles rising 

 through the liquid, due to the splitting up of the sugar into car- 

 bon dioxide and alcohol. The alcohol formed by the yeast can be 

 separated by distillation. 



Experiment 30. After the mixture is " working," shake and pour * 

 a little into a bottle and place it in the ice chest or in ice water for an 

 hour. Note the effect on the "working." 



142. The more Common Fermented Beverages. Taking 

 advantage of the great law of fermentation which dominates 

 the realm of nature, man has devised means to manufacture 

 various alcoholic beverages from a great variety of vegetable 



