292 STUDIES ON FERMENTATION. 



brought into the vertical plane passing over the rest of the 

 filament. In this way we will see the bright spot, the head 

 disappear, and then reappear. 



The chief inference that it concerns us to draw from the pre- 

 ceding facts is one which cannot admit of doubt, and which we 

 need not insist on any further — namely, that vibrios, as met 

 with in the fermentation of neutral tartrate of lime, are able to 

 live and multiply when entirely deprived of air. 



§ V, — Another Example of Life Without Air — 

 Fermentation of Lactate of Lime. 



As another example of life without air, accompanied by 

 fermentation properly so called, we may lastly cite the fermen- 

 tation of lactate of lime in a mineral medium. 



In the experiment described in the last paragraph, it will be 

 remembered that the ferment-liquid and the germs employed in 

 its impregnation came in contact with air, although only for a 

 very brief time. Now, notwithstanding that we possess exact 

 observations which prove that the diffusion of oxygen and 

 nitrogen in a liquid absolutely deprived of air, so far from 

 taking place rapidly, is, on the contrary, a very slow process 

 indeed ; yet we were anxious to guard the experiment that we 

 are about to describe from the slightest possible trace of oxygen 

 at the moment of impregnation. 



We employed a liquid prepared as follows : Into from 9 to 

 10 litres (somewhat over 2 gallons) of pure water the following 

 salts * were introduced successively, viz : — 



• Should the solution of lactate of lime be turbid, it may be clarified 

 by filtration, after previously adding a small quantity of phosphate of 

 ammonia, which throws down phosphate of lime. It is only after this 

 process of clarification and filtration that the phosphates of the formula 

 are added. The solution soon becomes turbid, if left in contact with air, 

 in consequence of the spontaneous formation of bacteria. 



