PRODUCED BY ALCOHOLIC FERMENTS. 189 



which I made in connection with this were published in 1883, 

 in ' Compte-rendu des travaux du laboratoire de Carlsberg.' 

 An account of the most important of the results is given 

 below, and then follow the later experiments made in more 

 recent years. 



I. Series of Experiments. From the sick beer of the brewery men- 

 tioned I separated the alcoholic ferments present, and obtained three 

 species namely, one belonging to the group Sacch. cerevisice (the main 

 constituent of the bottom yeast of the brewery), and two wild yeasts, to 

 which I gave the names Sacch. Pastorianns III. and Sacch. ellipsoi- 

 deus II* My problem was to determine whether one of the last two 

 species was the cause of the disease. With this object in view, I first of 

 all made a series of experiments with six two-necked flasks, each of which 

 contained 700 cc. of the same sterilised wort. Two of these flasks, 

 marked A, were inoculated with ij cc. of the species Sacch. cerevisice, 

 two others, marked B, were inoculated with i cc. of the same Sacch. 

 cerevisicz, and further with cc. of Sacch. ellipsoideus II., whilst the 

 remaining two flasks, C, were likewise inoculated with I cc. of the same 

 Sacch. ctrevisice and with cc. of Sacch. Pastor ianus III. In each case 

 the yeasts employed were thick, and of about the same consistency ; they 

 were pure cultures prepared under the same conditions, and they con- 

 sisted of young vigorous cells. The primary fermentation was carried on 

 at the ordinary room-temperature, the secondary fermentation during 

 storage at about 7 C. Two-necked flasks were also made use of for 

 the storage, and for this purpose were well filled with the respective 

 beers. After about three months' storage the beer was drawn off into 

 other sterilised flasks, and these were then set aside in a cupboard at the 

 ordinary room-temperature. In less than eight days it was found that 

 the beers from B and C were quite cloudy from suspended yeast, whilst 

 after fourteen days the beer from A was still faultless. 



It was thus shown that one of the three yeasts found in the 

 sick beer, namely ', Sacch. cerevisice, gave a stable product when 

 present alone in the fermenting liquid, but that tJie malady 

 manifested itself when, in addition to the above, either of the 

 other two species, no matter which, was also present under the 

 conditions named. 



In this, as in all the experiments which were undertaken 

 with the view to ascertain not merely the nature of the 



* With reference to these and the species mentioned later on, I would refer the 

 reader to the descriptions given in my ' Recherches sur la physiologic et la mor- 

 phologic des ferments alcooliques,' and also in the text books of Jorgensen and Zopf 



