340 LOUIS PASTEUR 



a greater refraction at that particular point, and leading us 

 to think that the diameter is greater at that extremity. We 

 may easily undeceive ourselves if we watch the movements 

 of the vibrio, when we will readily recognize the bend, 

 especially as it is 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 

 preceding 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 FER- 

 MENTATION OF LACTATE OF LIME 



As ANOTHER example of life without air, accompanied by 

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

 mentation 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 1 were introduced successively, viz: 



Pure lactate of lime 225 grammes 



Phosphate of ammonia 0.75 " 



1 Should the solution of lactate of lime he 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. 



:ncc 



