STUDIES ON FERMENTATION. 



213 



ferment formed in natural worts, had taken place. The 

 ferment, moreover, was very irregular, and comprised cells of all 

 sizes. We sowed some of it in a flask of pure wort. On 

 November 26th there was no apparent development : on 

 November 27th, however, not more than forty-eight hours after 

 impregnation, there was a considerable deposit of white ferment 

 at the bottom of the liquid, and fermentation was so active that 

 the surface of the liquid was covered with an abundant froth. 

 This shows us the wonderful vitality and recuperative power 

 possessed by germs which, left to themselves for about four 

 months, revived so readily. It proves too that the reviving 

 influences took efi'ect on some aerobian ferment. From the 

 mode of life of this latter being similar to that of a surface 

 fungoid growth, it does not become exhausted as the cells of 

 ordinary ferment do. Now the cells which, sown on August 

 6th, had become exhausted by prolonged stay in the mineral 

 liquid, and were almost inert, would have required several days 

 for their revival ; but in the experiment described the revival 

 was rapid, and this rapidity proves, as we have said, that the 

 revival must have taken place in cells of aerobian ferment. 



Taking some fresh yeast from the bottom of the liquid we 

 examined and made a sketch of it (Fig. 50). The field was 

 filled with round and oval cells, jointed and ramified filaments, 



Fig. 50. 



(9 



budding and multiplying in the most remarkable manner, 

 reminding us of the germination of the cells of yeast exhausted 



