18 



THE MICUOSCOPE. 



Feb. 



dine and finally viscose. Where does the substance come 

 from? Did it pre-exist in the wine in some soluble form, 

 and was it brought forth to be precipitated in this sticky 

 appearance by which we know it ? This opinion, held by 

 some scientists, seems now to have been abandoned. 



It is admitted that the viscose is the product of the 

 evolution of a special ferment in the same way as alcohol 

 and carbonic acid are products of Saccharomyces; but 

 there is a difference in opinion upon the nature of the fer- 

 ment which produces the viscose. 



M. Krammer [Annales agronomiques, 1890) has cul- 

 tivated in sterilized wine a ferment formed of very fine 



/ 



elongated sticks. This ferment planted in the sterilized 

 wines renders them viscid at the end of one or two 

 months. 



Pasteur has found in all the wines afl'ected as are these 

 which we are studying, a ferment formed of round glob- 

 ules which are not more than one micron in diameter, very 

 rarely isolated and more often united in long flexible 

 chains (fig. 1). It is to this ferment that nearly all con- 

 noisseurs attribute the formation of viscose. 



When it is developed in wine in the casks, a fraction 

 of it forms a scum on the surface, while the remainder is 

 deposited at the bottom. When found in wine in bottles 



