4 PURE CULTURES OF 



in 1889. (I am glad to be able to add that Pasteur took no 

 part in these attacks ; on the contrary, he publicly recognised 

 my work, in that at the end of 1886 he caused the award to 

 be made to it of the gold medal of the Societd d'Encourage- 

 ment pour PIndustrie Nationale.) The dispute has not yet 

 terminated. Velten constantly maintains that I was com- 

 pletely wrong in introducing into the brewery a pitching 

 yeast consisting only of a single race. A refutation of his 

 assertions will be found in the following pages. Prof. Duclaux, 

 whose sympathies were at first in the same direction as 

 Velten's. subsequently abandoned in some degree the latter's 

 views, and at the Brewers' Congress at Lille in 1890, he even 

 emphasised the fact that the yeast question had, as regards 

 low fermentation, been solved by my investigations. With 

 regard to high fermentation, he will still have nothing to do 

 with my system, and argues in favour of the introduction of 

 the old methods of Pasteur. The future will show that he is 

 wrong. 



L. Aubry, the director of the scientific station for brewing 

 at Munich, has expressed himself as follows on this question 

 ('La Gazette du Brasseur,' 1890, p. 79) : "Although we have 

 to deal mainly with the preparation of pure cultures of bottom 

 yeasts, it does not infrequently happen that we are asked for 

 pure top yeasts, and we have already introduced pure cultures 

 of such yeasts into practice and with good results. The 

 method which we have employed, in the case of both top 

 yeast and bottom yeast, has always been Hansen's method ; 

 we never make use of Pasteur's method. In the present 

 position of science, no one who is concerned with the pre- 

 paration of pure yeast will employ any other than Hansen's 

 method. The hostility which Hansen's efforts have aroused 

 is much to be deplored. We all recognise, and Hansen no 

 less than any, what Pasteur has accomplished in connection 

 with the yeast question, but this does not prevent us from 

 perceiving that a new direction has been given to the question 



