412 MICRO-ORGANISMS AND FERMENTATION. 



fundamental alterations caused by other micro-organisms, 

 and amongst them, according to Wortmann, Mycodermas 

 take the first place. By their agency, alcohol is converted 

 into carbon dioxide and water, and they also influence the 

 amount of acid and destroy the bouquet. A wine may become 

 filmy, and may deteriorate in time without a visible covering 

 of film appearing on its surface. The suspended cells of 

 Mycoderma, which need not be numerous, may bring about 

 in the course of years the same action which would occur more 

 rapidly when the cells form a coherent mass on the surface. 

 Mycodermas which often inhabit corks (like the moulds) may 

 impart the well-known corked taste to wine. 



Will has isolated a Mycoderma from top-fermentation beer, 

 which brings about a marked decolorisation of beer. This 

 occurs within a short time at the high temperatures requisite 

 for completing top-fermentation. The species develops a 

 large amount of acid in beer, but under certain conditions 

 a destruction of acid may also take place. It cannot bring 

 about alcoholic fermentation. 



Will also made a series of observations concerning the 

 duration of life in wort-cultures and in the dry state, and with 

 regard to the power of resistance to heat in liquids. Seifert 

 closely examined two Mycoderma species isolated from wine, 

 which produced from 0-064 to 0-904 per cent, of acetic acid 

 in an ordinary Austrian white wine, and reduced the amount 

 of alcohol. The Mycoderma investigated by Heinze (If. 

 cucumerina, Aderhold) was derived from a fermentation of 

 sour cucumbers : he declares it to be a dangerous enemy 

 of lactic acid fermentation. In beer the organism attacks 

 alcohol strongly, and produces a bitter flavour. It is capable 

 of producing alcoholic fermentation in 'dextrose solutions. 

 In cider, with 10-62 grammes of sugar, it yielded 4-34 grammes 

 of alcohol per 100 c.c. of fermented liquid, in five minutes, at 

 25 C. There is no fermentation with maltose, saccharose, 

 and lactose. Heinze also closely investigated the question 

 of acid production and acid destruction. 



Henneberg mentions two species of Mycoderma, which 

 he frequently found in distillery and pressed yeast. The 

 shape of the cells is very varied. The one species frequently 



