THE BITTERING OF WINE 311 



discoloration of freshly broken or cut surfaces in the body of the fungus, is well 

 known. The bluing of two of these, which he styled Boletus luridus and 

 Agaricus sanguineus (?), was explained by OH. SCHONBEIN (I.) in 1856, by stating 

 that these fungi contain a resinous substance soluble in alcohol (the above- 

 mentioned reaction with guaiacum tincture will be remembered !), and becoming 

 converted into a blue oxy-compound when brought into contact with ozone. 

 The formation of this latter from the oxygen of the air is accomplished by the 

 activity of another substance, also present in the fungi, and destructible by heat. 

 This active substance was subsequently (in 1895) proved by E. BOURQUELOT and 

 G. BERTRAND (I.) to be an oxydase, and was detected by them in 59 out of 107 

 species examined : e.g. in 18 species of the genera Russula and Lactarius, 

 10 species of the genus Boletus, 2 species of the genus Amanita, &c. According 

 to the researches of BOURQUELOT and BERTRAND (II.), the enzyme giving rise to 

 the bluing of Boletus cyanescens is similar to laccase ; but another oxydase, 

 causing the freshly fractured surfaces of Russula nigricans to first turn red and 

 finally become black, is certainly different. 



G. TOLOMEI (VI.) discovered in ripe olives an oxydase which he called olease. 

 In many parts of Italy it is customary to allow the olives, before putting them 

 through the press, to undergo a spontaneous decomposition, which is chiefly 

 effected by this olease, but has not yet been sufiiciently investigated. This 

 enzyme also passes into the oil prepared at temperatures below 70 0., and pre- 

 sumably continues to convey oxygen gradually thereto as well, oleic acid, acetic 

 acid, sebacic acid, &c., being formed. 



Another phenomenon not yet accurately known (but possibly also attributable 

 to enzymatic activity) will now be considered, since otherwise no convenient 

 opportunity would offer, and that is 



216. The Bittering of Wine. 



This malady makes its appearance in many districts, such as the French Jura 

 (Burgundy wine), the Ahr valley (Rheinland), Voslau near Vienna, and Sicily 

 (Vino del Faro di Messina), with comparative frequency, and almost exclusively 

 affects red wines. The commencement of the disease is evidenced by a reduction 

 in the acid content, the wine becoming apparently sweeter again (French cellar- 

 masters say "le vin doucine"). By degrees the liquid turns paler, and is finally 

 decolorised completely, the colouring-matter being deposited as an insoluble 

 sediment or covering the walls of the bottle as with a skin. Concurrently, the 

 wine develops a strange odour and a bitter after-taste, which finally becomes so 

 strong as to render the liquid undrinkable. This malady first makes itself 

 apparent in the second or third year of storage, and oftentimes not before the 

 wine is bottled for maturing. 



Respecting the cause of this incurable disease of wine, nothing reliable can 

 as yet be stated. PASTEUR (XVI.) attributed it to the activity of a rod-shaped 

 fission fungus, without, however, being able to throw any further light on the 

 matter. The bacteria found in large numbers in bitter wine are for the most 

 part covered with flakes and fragments of the precipitated brownish red colouring- 

 matter, and hence very often assume remarkable shapes. They may be freed 

 from these incrustations by the addition of a droplet of a solvent mixture of 

 alcohol and tartaric acid to the preparation. R. ADERHOLD (I.) unsuccessfully 

 attempted to prepare pure cultures of the organism suspected of causing this 

 malady, but PERRONCITO and MAGGIORA (I. ) were able to artificially induce the 

 complaint in sound wines by inoculating them with a bouillon culture of 

 microbes discovered in bitter wine ; the infection, however, succeeding only in 

 such samples as contained less than 8.5 per cent, of alcohol. The attempts at 



