80 STUDIES ON FERMENTATION. 



From the previous facts it is obvious that there exist certain 

 productions of various aspects, the germs of which are parti- 

 cularly abundant in the dust of a laboratory where the pheno- 

 mena of fermentation are studied, productions essentially aerial, 

 and incapable of giving rise to fermentation, although it may 

 be impossible for the microscope to distinguish their forms from 

 those of true alcoholic ferments. 



The idea of some physiological bond between these plants and 

 the ferments which resemble them in so remarkable a manner, 

 is one that impresses itself forcibly and, so to say, instinctively 

 upon the mind. This remark holds good also in the case of 

 mycoderma vim, properly so called, when compared with 

 alcoholic ferments. There appears to be no other difference 

 between the mycoderma vini and the torulce of which we are 

 speaking, than that afforded by peculiarities of physical structure 

 and a certain greasiness in the cells of the former which permits 

 it to exist, in the form of a scum, upon the surface of liquids, 

 that is to say unsubmerged. 



We have frequently, but without success, endeavoured to 

 bring about the conversion of these unsubmerged torn Ice and 

 mycoderma vini into alcoholic ferments ; in other words, we 

 have never succeeded in imparting to these torulm or to myco- 

 derma vini, which bear so striking a resemblance to alcoholic 

 ferments, the permanent fermentative character peculiar to the 

 latter. At one period of our researches, in 1862, and more 

 recently, in 1872, we thought that we had discovered the con- 

 ditions under which such conversion might be possible, but, as 

 we shall explain in a subsequent chapter, our experiments 

 were affected by certain errors that had escaped our notice. 



* It is possible that this greasiuess in the cells of the common mycoderma 

 vini arises simply from the composition of the liquid in which it vegetates. 

 It is in saccharine liquids that the submerged toruJoi are found; fer- 

 mented liquids more readily give birth to the forms of toruJcc and myco- 

 derma vini which exist as a scum. In all probability, however, there is 

 no radical diflference between these two kinds of little cellular plants of 

 aerial growth, the floating torulw and mycoderma vini. 



