312 THE OXYDASES 



noculation made by E. Kramer with a bittered white wine from the province of 

 Kiistenland (Austria) did not prove satisfactory. At present, uncertainty pre- 

 vails not only with regard to the organism causing this complaint and the 

 external conditions influencing its development, but also as to the nature of the 

 bitter principle itself. The opinion expressed by Mulder, that citric ether is in 

 question, was refuted by C. NEUBAUER (I.), who proved that this (still uninvesti- 

 gated) bitter principle is a compound that is not volatilised by boiling the wine. 

 From experiments made by J. BERSCH (I.), it is permissible to conclude that the 

 tannin present is decomposed and consumed by the organisms here in question. 

 This observation would suffice to explain the fact mentioned at the commence- 

 ment of this paragraph, that bittering is almost exclusively confined to red wines, 

 these containing, as is well known, a somewhat large amount of tannin absorbed 

 from the skins and kernels of the grape during the primary fermentation. 



It may be useful to casually mention, in conclusion, that the bittering of 

 alcoholic beverages, beer in particular, may also be occasioned by higher fungi 

 (yeasts). Fuller particulars will be found in a subsequent chapter in the second 

 volume, dealing with tiaccharomyces Pastorianus, and to which the reader is 

 hereby referred. 



END OF VOL. I. 



Printed by P.AI.I < 'o.Mi'ANv LTD. 



Tavistock Street, Covent Garden, London 



