THE MICROBE OF VINEGAR 103 



covers the entire surface. This film is simply a 

 thin network of microbes. 



The members of this entire working force now, 

 subsisting on oxygen breathed from the air and 

 other substances at the surface of the cider, by 

 their life processes convert the alcohol of the cider, 

 first into aldehyd, and then into acetic acid, or 

 vinegar. 



The entire work may require several weeks, or 

 even months. But when the job is complete, the 

 owner has a barrel of the best vinegar in the 

 world. 



The work of these minute beings in making vine- 

 gar is just as natural as a similar work done by 

 all air breathing animals, including ourselves. We 

 breathe oxygen with the air that we may live. The 

 oxygen in the lungs unites with carbon as waste 

 from the blood, and forms carbonic acid, which we 

 exhale with every breath. So the microbes of 

 vinegar breathe oxygen from the air that they may 

 live. The oxygen comes in contact with the alco- 

 hol of the cider, and the final result is acetic acid 

 or vinegar. To complete the analogy, the carbonic 

 acid which we manufacture serves as food for 

 vegetables; and the acetic acid or vinegar, which 

 these tiny creatures manufacture, serves as a 

 dietetic principle in various foods which we con- 

 sume. 



Evidently this microbe may be, is, cultivated. 

 In the home where vinegar is only occasionally 



