656 THE CLOUDING OF WHITE WINE, 



In endeavouring to discover the constituents of wine which 

 favour the development of the bacterium I emploj^ed nutrient 

 agar, to which various substances had been added. In the first 

 place, alcohol obtained by distilling wine produced a slight growth. 

 A similar growth was also obtained by the addition of levulose 

 and of lactose. Maltose, dextrose and sucrose were without 

 influence, while the addition of a small quantity of tartaric acid 

 (to make 0*3%) to the carbohydrates hindered the development of 

 the organism. Dextrin, glycerol and succinic acid were likewise 

 inoperative. No growth took place in Hansen's peptose-glucose 

 with or without the addition of gelatine. From these experiments 

 it would appear probable that the one particular constituent of 

 wine that is active in stimulating the growth of the organism is 

 alcohol. 



The obligate aerobic character of the bacterium, and the ten- 

 dency that it has for forming films upon the surface of fluids, are 

 suggestive of the acetic bacteria. With the object of determining 

 the production of acid a culture was smeared over a plate of 

 wine-litmus-lactose-agar and incubated at 22°. The litmus in the 

 vicinity of the culture was reddened. As this might be due to 

 the formation of lactic acid from the lactose or acetic acid from 

 the alcohol, a plate of nutrient agar, to which had been added 

 alcohol (wine distillate) and chalk, was smeared with a culture of 

 the organism. The chalk in the vicinity of the growth was 

 dissolved, and the agar, when microscopically examined, was found 

 to be transparent and to contain no crystals. A chalk plate 

 without alcohol was unaffected. From these experiments the 

 bacterium appears to belong to the group of acetic-acid-forming 

 bacteria. 



My first impression was that the trouble might have originated 

 in the corks with which the bottles were fastened, a view engen- 

 dered by the observation that the cork of the first bottle 

 contained a number of minute crevices in which the microscope 

 revealed the greenish colour of fruiting Penicillium ylaueum; 

 while plate cultures from fragments of the cork produced the above 

 mentioned hyphomyces and a variety of yeasts. This idea was, 





