SCIENTIFIC RESEARCH IN PRACTICE. 275 



sine qua non. The results of practical experiments have clearly 

 proved that this is possible. 1 



"We now know from experience gained in the course of 

 many years that the suppression of the numerous varieties of 

 organisms existing in must and originating from berry-skins 

 mould-fungi, wild yeasts, Mycoderma, and bacteria frequently 

 leads to a radical improvement of the fermentation-products, 

 and that the suppression of those detrimental organisms may 

 be effected by yeasts of different types, that is, definite action 

 in other words, we know that the beneficial results referred to 

 can be secured by the use of pure yeast in the fermentation of 

 grape-, fruit-, and berry-juices. This improvement in smell 

 and taste of the wine often manifests itself during fermentation, 

 and at all events after it has ceased. Moreover, the beneficial 

 effect of pure yeast does not end here. For during fermen- 

 tation the pure yeast has not only asserted its fermentative 

 activity, but has also checked, if not entirely prevented, the 

 growth of the entire crowd of organisms occurring spon- 

 taneously in the must and originating from the berry^skins, 

 among which organisms unsuitable yeasts and even directly 

 disease-producing species, such as Mycoderma, acetic-acid 

 bacteria, etc., are never wanting. Thus, not only the must, but 

 also the fermentation-product, the wine, in all its further stages, 

 is subject to the domination of the pure yeast. Hence, the beneficent 

 influence of the pure yeast will not only make itself felt during 

 the period immediately following the end of the principal 

 fermentation, but it will continue. This is likely to be 

 specially advantageous to the development of wine in bottles 

 owing to the pure yeast present exercising a repressive 

 influence on other organisms. It may be added that all 

 experience capable of exact control, gained since the intro- 

 duction of pure yeast into practice in wine-manufacture, goes 

 to prove the great and lasting influence of pure yeast on the 

 fermentation-product. " 2 



1 " On the Experience hitherto obtained in Practice regarding Pure Yeasts." 

 A paper read at the thirteenth German Congress of Viticulture at Maintz, 

 1894. See also WORTMANN'S very instructive treatise, "The Use and Effect of 

 Pure Yeasts in the Manufacture of Wine," Berlin, 1895. 



2 "On Artificial After-fermentations of Wines in Bottle and Cask," 

 LandwirtschaftL Ja/irb., 1897. 



