THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[THIRD SERIES.] 

 No. 65. MAY 1863. 



XXXIV. — A Novel Instance of the Production of Fermentation 

 by the Presence of Infusoria capable of existing without free 

 Oxygen and deprived of all Access of Atmospheric Air. By 

 M. L. Pasteur. 



Such is the subject of a short paper addressed by M. Pasteur 

 to the French Academy of Sciences, and published in the 'Comptes 

 Rendus' for March 1863. 



About two years previously, he communicated a note to the 

 same learned body respecting the existence of infusory ani- 

 malcules possessing the two properties of living without free 

 oxygen, and of acting as ferments*. "These were," he says, 

 " the first known examples of an animal ferment, as well as of 

 animals capable of living and of indefinite self-multiplication, 

 without contact with atmospheric air, whether in the gaseous 

 state or held in solution. 



" The infusory animalcules in question constitute the ferment in 

 butyric fermentation, which has hitherto been explained to take 

 place by the agency of plastic azotized matters, more or less 

 changed by contact with the air, upon sugar or lactic acid, and 

 by the supervention of an internal molecular action giving rise 

 to the phenomena of fermentation. 



" I believe I have proved that such a theory, which is applied 

 indeed in explanation of all kinds of fermentation, properly so- 

 called, is inadmissible, and that an albuminoid matter never 

 constitutes a ferment, but that the true ferment (as in butyric 

 fermentation, for example) is an organized being belonging to 

 the Vibrios, derived from the air and present in the fermentable 

 substance. 



" I am now able to add another example — viz. the fermenta- 

 tion of tartrate of lime, determined in precisely the same way 

 * See Annals, April, 1861, p. 343. 



Ann. fy Mag. N. Hist. Ser. 3. Vol. xi. 21 



