240 Dr. TnOMSON on the Vinegar Plant. 



vegetate iu a position of immersion in a liquitl, it must possess a power 

 of extracting nom-ishment from the fluid atmosphere with which it is 

 surrounded, just as sea and water plants eifect their object. It is, how- 

 ever, impossible that in a solution of pure sugar the vinegar plant can 

 increase from the influence of vinegar and any albuminous substance, as 

 has been asserted (Mulder Scheid. Onderz Deel. i. 539,) to be the mode 

 of its propagation, since the presence of the vinegar plant precedes the 

 formation of the vinegar in the trials detailed. If the numerous experi- 

 ments of various chemists are to be depended on, it is certain that the 

 cellular structure of the vinegar plant, consisting of cellulose chiefly, must 

 derive its carbon from the carbonic acid of the sugar, in absence of com- 

 mon air, or possibly from the atmosphere, in its presence, which may also 

 supply it with nitrogen for its albuminous constituent; or the nitrogenous 

 princijjle, like the salts, may be capable of a greater difi"usion, without 

 any considerable increase in its original amount. 



Formation of Vinegar. — The circumstances most favourable to the 

 production of vinegar from sugar are, when a vinegar plant is introduced 

 into an open shallow vessel, containing a solution of sugar or treacle. 

 The plant exposes its upper layer near the surface of the solution, and 

 augments by the deposition of a new layer or stratum above the old 

 plant, to which it is attached, but both can readily be separated simply by 

 lifting up the superincumbent layer. It is thus worthy of notice, that the 

 new growth takes place between the old plant and the atmosphere that 

 is in closer contact with the air. My observations tend to show that 

 when the vinegar plant falls to the bottom of a deep vessel filled with a 

 saccharine fluid, the progress of the acetification is mucb more slow than 

 when the plant is in contact with the air. The action of a cellular 

 plant is, under these circumstances, analogous to that of a porous body 

 which is capable of condensing oxygen from the atmosphere, to a condition 

 approximating to fluidity upon the area of its wall cells. The action of 

 spongy platinum and platinum black in the absorption and condensation 

 of oxygen, are sufficiently well known ; and through this power, of oxidizing 

 and acidifying, hydrous oxide of methyle into formic acid, and alcohol 

 into vinegar. The absorption and retention of air in the cells of the 

 vinegar plant may assist in explaining the fact, which is particularly 

 noticed by Kutzing and Schmidt, that it is distinguished by its floating 

 at the surface of the fermenting fluid, while the yeast globules remain at 

 the bottom of the liquid. 



The influence of cellular plants in decomposing the higher oxides, in 

 consequence of their absorptive action on oxygen, is well exemplified in 

 the case of yeast globules, which, when brought in contact with binoxide 

 of hydrogen, speedily cause the removal of the second atom of oxygen. 

 (Liebig Ann, v. 211.) This action seems quite parallel to that of porous 

 paper on certain coloured solutions, as the red solution of permanganate 

 of potash, and the amethyst solution of ferrate of potash, the former of 

 which is slowly, the latter with great rapidity, deprived of tint when 



