STUDIES ON WINE. 115 



upon the quality of the liquid. Besides the myco- 

 derma aceti, which is the agent of acetification, there 

 is another mycoderm called mycoderma vini. This 

 one deposits nothing which is hurtful to the wine, 

 and its flowers are developed by preference in new 

 wines, still immature, and preserving the astringency 

 of the first period of their fabrication. 



The requirements of the two sorts of flowers are 

 such that even when the flower of vinegar is sown on 

 the surface of a new wine, no development takes 

 place. Conversely, the mycoderma vini sown on wines 

 that have grown old in casks or in bottles will 

 refuse to multiply. The mycoderma vini produces 

 no alteration in the wine ; it does not turn the wine 

 acid. In proportion as the wine grows old the flower 

 tends to disappear, the wine ' despoils ' itself, to 

 use a technical expression ; physiologically speaking, 

 the wine loses its aptitude to nourish the mycoderma 

 vini, which, finding itself progressively deprived of 

 appropriate nourishment, fades and withers. But it 

 is then that the mycoderma aceti appears, and multi- 

 plies with a facility so much the greater that it draws 

 its first nourishment from the cells of the mycoderma 

 vini. The mycoderma aceti has played so large a part 

 in the early pages of this book that it is not necessary 

 to go back upon it here. 



There is another disease very common among 

 wines when the great heat of summer begins to make 



