184 STUDIES ON FERMENTATION. 



brought about several spontaneous fermentations, the germs of 

 which could have been introduced by notliing but the particles 

 of dust in the air. These fermentations, which we were 

 obliged to follow very carefully with the microscope from the 

 time when they first manifested themselves, on account of the 

 transformation that we were seeking, which transformation we 

 thought might possibly be that of the cells of mycoderma vini 

 into cells of ferment, generally gave us during the first days 

 of fermentation the large, elongated, branch}'- ferment repre- 

 sented in Plate X., which was succeeded by the small ferment 

 represented in Plate XI.* 



Here let me describe one of these experiments. In the begin- 

 ning of March, 1872, we grew some mycoderma vini, obtained from 

 wine, on some wort contained in a shallow basin. On March 6th 

 we submerged the efilorescence and put it all together, liquid and 

 film, into a long-necked flask. On March 9th we detected in- 

 cipient fermentation, and on March 12th we took a sketch of the 

 yeast of the deposit, as given in Plate XII. This is the large 

 and long branching, more or less pear-shaped form, which 

 occurs at the beginning of fermentation in thj sweet and acid 

 musts of our domestic fruits. On March 16th we made another 

 sketch of the deposit, in which the proportion of cells, in the 

 form of elongated segments and filaments, reminded us, in 

 some measure, of the filamentous mycelium of typical fungoid 

 growths much diminished. In this case, however, the majority 

 of cells were oval, round, and in short segments. On this 

 day, March 16th, we added some fresh wort to that whicii 

 had fermented, with the object of prolonging the duration of 



* In these experiments the apiculated ferment appeared sometimes, 

 but much less frequently than aaccharomyces pastorianus. We also met 

 with the ellipsoidal ferment. We should probably have a greater variety 

 of ferments if our experiments could be conducted in the open air, but 

 insects and particles of dust of all kinds brought by the wind render 

 experiments under such conditions difficult and untrustworthy. In a 

 laboratory we have not these difficulties to contend against, but, unfor- 

 tunately, the operations ordinarily carried on there cause the results of 

 our experiments to bo of a less general character than they would be if 

 obtained in free contact with country air. 



