264 MICRO-ORGANISMS AND FERMENTATION. 



has invariably confirmed the correctness of our first results, 

 viz., in high- as well as in low-fermentation the whole 

 fermentation can be carried through with a single selected 

 type of yeast. 



HANSEN'S epoch-making investigations of the last decade 

 have given rise to a very extensive literature, much of which 

 records original work of great value, throwing light on his 

 system from many sides, and thus facilitating both a true 

 conception of its importance and its practical application. 



It would lead us too far to discuss all the principal points 

 embodied in the literature. In concluding this description, we 

 will confine ourselves to a few quotations from the highest 

 authorities, those who have contributed to the elucidation of 

 our subject and to the extended adoption of the system in 

 different countries. 



Professor C. LINTNER gives the following review of the 

 situation in 1885: l 



" Now that different breweries have employed pure cultiva- 

 tions of the Carlsberg yeasts, and that the Scientific Station at 

 Munich has also introduced pure cultivations of Munich yeasts 

 into various breweries, the results obtained may be summarised 

 as follows : 



" 1. By contamination with so-called wild yeasts, a brewery 

 yeast, normal in other respects, may gradually become 

 incapable of producing a beer of good flavour and 

 with good keeping properties. 



" 2. A contamination of this kind can occur through wild 

 yeasts present in atmospheric dust during summer 

 and autumn, or the wild yeast may be introduced 

 with the pitching-yeast or with cask sediment. 

 " 3. By means of HANSEN'S methods of analysis and pure 

 cultivation, it is possible to isolate from a contamin- 

 ated yeast the desired brewery yeast in a good and 

 pure condition. 



" 4. The pure cultivated yeast possesses in a marked degree 

 the properties of the original yeast previous to 

 1 Zeitschrift f. d. ges. JBrauw., 1885, p. 399. 



