MYCODERMA. . 41 1 



cases strongly affected. Acetic acid reacts strongly with a 

 few species ; in other cases the species cannot grow at all . 

 in a solution containing acetic acid. 



Alcohol, the sugars, glycerine, and tannic acid are decom- 

 posed. Alcohol is converted by an oxidation process into- 

 carbon dioxide and water, but may also act as an organic 

 foodstuff. As early as 1878 Schulz found that " the film 

 fungus can produce within itself ready formed organic com- 

 pounds, and requires nothing but ammonia and alcohol for 

 the purpose." Schulz did not, however, work with pure 

 cultures. 



Meissner utilised for his experiments both the nitrogenous- 

 nutritive material used by Schulz (ammonium nitrate, aspar- 

 agin, ammonium tartrate) and an artificial solution containing 

 ammonium phosphate and ammonium chloride, together with 

 the necessary mineral constituents. The vigorous growth 

 of Mycoderma proves that these two solutions supply them 

 with nitrogen. Consequently the alcohol of the nutritive 

 solution is partially respired and partially utilised for the 

 building up of the cells. With regard to the sugars, Meissner 

 found that the Mycoderma species cultivated on sterile grape 

 juice respired dextrose and laevulose to some extent, partially 

 producing acids from them. On artificial nutritive solutions 

 which contain dextrose or saccharose as the only organic 

 substance in addition to the necessary mineral nutrients, the 

 sugars are oxidised, part being utilised for the construction of 

 new cells, and part for the fresh formation of acid. Glycerine 

 is not only destroyed, but may be produced from other organic 

 substances. This fact was confirmed by W. Seifert. 



The Mycodermas also produce various volatile acids. Thus 

 Wortmann has drawn attention to the fact that many wines 

 which have become filmy have an odour which resembles 

 rancid butter to an extraordinary degree. Butyric acid has 

 been formed in these cases. 



Lafar found in a cask store a Mycoderma which imparted 

 a flavour to beer resembling wine ether. Non-volatile acids 

 and esters are also formed. 



In finished wines the yeast has generally, but not always, 

 finished its special work, but nevertheless wine may undergo 



