THEORY OF THE FORMATION OF VINEGAR. 



25 



losing any of its inherent properties, effects chemical combination, 

 the alcohol undergoing slow combustion, and being converted into 

 acetic acid. In order that the reaction may continue, it is, of 

 course, necessary to present fresh oxygen to the platinum to re- 

 place that which is withdrawn. The two actions then go on 

 side by side. 



This can be illustrated by an apparatus similar to Fig. 1. It 

 consists of a bell glass through the mouth of which a long funnel 

 passes ; the lower end of this funnel terminates in a fine point, 

 so that the alcohol poured in may 

 percolate very slowly. The vessel 

 is placed upon supports within a 

 dish in which is a saucer or small 

 flat basin containing the platinum 

 black. The interstice between the 

 bottom of the dish and the bell 

 serves for the circulation of air in 

 the jar. On pouring the alcohol 

 through the funnel, in the course of 

 a short time the odor of acetic acid 

 is perceived at the mouth from the 

 acetic acid vapors, which are gene- 

 rated. These condense on the sides 

 of the jar and trickle to the bottom, 

 where they collect in the vessel in 

 the dish. It is advantageous for the 



success of the experiment to have the alcohol heated to about 90 

 F. when it is poured in. By washing and glowing the platinum 

 used for the oxidation of alcohol, it can be again employed for 

 the same purpose. 



Independently of the purely chemical methods which, with the 

 exception of that by which acetic acid is produced by the dry 

 distillation of wood, are of no practical importance, the forma- 

 tion of vinegar, no matter what method may be adopted, can only 

 be effected in the presence of certain organisms. It has long 

 been known that organisms to which the term mother of vinegar 

 has been applied,- develop upon fluids containing, besides alcohol, 

 certain other substances, for instance upon weak wine and beer, 





