The Minute Structure of the Vinegar Plant. 247 



alcohol into acetic acid, and that the mycoderm of wine 

 converted the alcohol into water and carbonic acid. Thus 

 both act as oxydisers, and it is well known that if the 

 vinegar plant be left in a fluid after it has transformed the 

 sugar or alcohol into vinegar, it then burns up the vinegar, and 

 leaves the housewife, or other manufacturer, who has neglected 

 to remove it at the right period, only dirty water for her pains. 

 M. Pasteur also tells us that the vinegar plant cannot acetify 

 when it is submerged, while, as the German unterhefe yeast 

 proves, the wine or beer fermentation can be excited by a 

 yeast plant at the bottom of the fluid. These facts suggest 

 inquiries into the action of different portions of a thick vinegar 

 plant, of which one part is always under the fluid. 



It seems to the writer that Professor Graham's researches 

 into dialysis afford a probable explanation of the actions of small 

 plant cells in the cases adduced. Their delicate membranes 

 give a preferential passage to one substance over another, and 

 they may permit new combinations to be formed by allowing 

 them the means of getting out of the way of those from which 

 they were derived. They present oxygen to a compound, and 

 if certain of its atoms choose to take it, they can escape with 

 the new object of their chemical attachment. Thus the process 

 bears some resemblance to the decompositions effected in water 

 when that fluid allows the new resulting compound to fall as 

 a precipitate, or escape as a gas. 



M. Bechamp states that acetic acid is one of the products of 

 vinous. fermentation, and the fact is accepted by M. Pasteur. 

 M. Maumene disputed it, declaring that all well-made wines 

 contained no acetic acid. This brought a rejoinder from M. 

 Bechamp, to the effect that acetic acid is found even in the must 

 of grapes. M. de Luca examined sixty-seven wines of Tuscany, 

 and found acetic acid in all. M. Pasteur found that if a small 

 quantity of vinegar was introduced when the Mycoderma vini 

 was growing in an alcoholic liquid in contact with air, it dis- 

 appeared, and he never obtained acetic acid from the growth 

 of that plant in a liquid of this kind. These facts seem to show 

 that the vinegar plant is present in all alcoholic fermentations, 

 and exerts some action, although the chief and prevailing action 

 is that of the Mycoderma vini, which is antagonistic to it, not- 

 withstanding its analogous character. 



Here I leave the question for the present. I have brought 

 forward certain facts which I think important, and many con- 

 jectures which may stimulate inquiry, if they are not of any 

 other use. The subject is within the reach of thousands of 

 microscopists who habitually read the Intellectual Observer ; 

 and I shall be much obliged if any of them will favour me with 

 any new information they may collect. 



