86 , LOUIS PASTEUE. 



together without order or disposed in layers after hav- 

 ing been rolled up like the spring of a watch. Openings 

 formed in the sides of the barrel, and in a double 

 bottom upon which the shavings rest, permit the 

 access of the air, which rises into the barrel as it 

 would in a chimney, and yields all or part of its 

 oxygen to the alcohol to convert it into acetic acid. 

 All writers prior to Pasteur, and Liebig in particular, 

 maintained that the shavings acted like porous bodies 

 in the same manner as finely divided platinum. The 

 acetic acid, they said, was formed by a direct oxidation, 

 without any other influence than the porosity of the 

 wood. This view of the subject was rendered plausible 

 by the fact that in many manufactories the alcohol 

 employed is that of distillation, which contains no al- 

 buminoid substances. Moreover, the duration of the 

 shavings is in a sense indefinite. 



According to Pasteur, the shavings perform only a 

 passive part in the manufacture. They promote the 

 division of the liquid and cause a considerable aug- 

 mentation of the surface exposed to the air. They 

 moreover serve as a support for the ferment, which is 

 still, according to him, the mycoderma aceti, under the 

 mucous form proper to it when submerged. 



Certainly appearances were far from being favour- 

 able to this view. When the shavings of a barrel 

 which has been in work for several months or even for 

 several years are examined, they are found to be extra- 



