314 M. L. Pasteur on the Production of Fermentation 



by the presence of an infusory animalcule, existing without free 

 oxygen, belonging also to the genus Vibrio, though very dif- 

 ferent, at least in external aspect, from the animalcule of butyric 

 fermentation. 



" To be brief, I will at once adduce a decisive experiment in 

 proof of this statement. I place in an aqueous solution of tar- 

 trate of lime a minute portion (some milliemes) of phosphate of 

 ammonia or of alkaline and earthy phosphates, either artificially 

 prepared, or derived from the ashes of the yeast of beer or the 

 ashes of infusory organisms. (I prefer the ashes obtained by the 

 combustion of organisms analogous to those whose development 

 is sought, in order to be more certain that no useful principle, 

 known or unknown, is omitted. It is probably as well to add 

 some traces of sulphate of lime and of ammonia.) 



" The vessel used is a glass phial, flat at the bottom, and 

 having a curved glass tube fitted in its narrow neck. The tar- 

 trate of lime is introduced, the phial filled up with pure water, 

 and then placed in a chloride-of-calcium bath with the end of 

 the curved tube immersed in a vessel of boiling water. Its con- 

 tents are made to boil, in order to expel all the air held in solu- 

 tion ; and when this is effected, the surface of the water under 

 which the end of the curved tube opens is covered by a thick 

 layer of oil. The whole apparatus is then left to cool for some 

 hours. Under these conditions, the tartrate shows no sign of 

 fermentation ; but if a small quantity of the Infusoria obtained 

 from a spontaneously fermenting portion of tartrate of lime be 

 quickly introduced within the phial, and the little water dis- 

 placed in this process be as quickly replaced by some of the 

 water deprived of its air by boiling, then it is found that the 

 introduced Infusoria rapidly multiply, and the tartrate progres- 

 sively disappears until entirely removed, all air having been in 

 the meanwhile excluded by the curved tube of the phial being 

 kept under the water, or, better still, under the surface of a 

 mercury bath. 



" The tartrate was replaced by a deposit consisting solely of 

 the bodies of Vibrios, of about jtjo o iiiillimetre in diameter, but 

 so variable in length that some measured -^^ millimetre. Like 

 all Vibrios, they are reproduced by fission ; and during the act 

 of fermentation, the minutest quantity of the deposit formed by 

 them showed them in more or less rapid and writhing move- 

 ment. 



'' The fermentation of tartrate of lime, therefore, whatever its 

 intimate cause may be, is set up by the presence of Infusoria 

 having the property of living without free oxygen and without 

 contact with atmospheric air. 



" It may undoubtedly be objected that, at the moment when 



