THE BEGINNINGS OF LIFE. 



405 



les fermentations proprement elites, visqueuse, lac- 

 tique, butyrique, la fermentation de 1'acide tartarique, 

 de 1'acide malique, de 1'uree . . . . , etaient toujours 

 correlatives de la presence et de la multiplication 

 d'etres organised. Et, loin que 1'organisation de la 

 levure de biere fut une chose genante pour la theorie 

 de la fermentation, c'etait par Ik au contraire, qu'elle 

 rentrait dans la loi commune, et qu'elle etait le type 

 de tous le ferments proprement dits. Selon moi, les 

 matieres albuminoides n'etaient jamais des ferments, 

 mais I'aliment des ferments. Les vrais ferments etaient 

 des tres organised.' (Loc. cit. p. 23.) 



Thus it may be seen that there are two principal 

 doctrines as to the nature of a ( ferment,' each 

 having its several supporters ; so that two distinct 

 theories of fermentation at present divide the world 

 of chemists. Some now believe in the exclusive view 

 resuscitated by M. Pasteur 1 , that (i) all ferments are 

 living organisms these being upholders of what may 

 be called a c vital theory of fermentation;' whilst 

 others maintain (2) that certain not-living albumenoid 

 substances are also capable of acting as ferments, so 

 that they may be classed as believers in a c physical 

 theory of fermentation.' Of those who maintain the 

 latter opinion, the great majority believe with Gay- 

 Lussac, that the presence of oxygen is necessary in 

 order to arouse the activity of the ferment ; though my 



1 Liebig says : ' It is impossible to detect any fundamental difference 

 between the views of Turpin and those of Pasteur.' 



