36 LOUIS PASTEUR. 



properties of the group which acts in the opposite 

 manner. The resultant effect of these actions, some- 

 times concordant, sometimes antagonistic, would cease 

 to be alike in absolute quantity. And if this be the 

 necessary condition of similitude as to molecular 

 arrangement, this similitude would cease to exist, and 

 with its disappearance would appear all the differences 

 of chemical and physical properties which constitute 

 its outward manifestations. 



The facts were found to harmonise with these 

 logical deductions. After having made dissymmetry 

 intervene as a modifier of chemical affinity, he had a 

 strange and manifest proof of the influence of dis- 

 symmetry in the phenomena of life. 



It had been long known, through the observations 

 of a manufacturer of chemical products in Germany, 

 that the impure tartrate of lime of commerce, if con- 

 taminated with organic matters and permitted to 

 remain under water in summer, would ferment and 

 yield various products. Pasteur caused the ordinary 

 right-handed tartrate of ammonia to ferment in the 

 following manner : He took some very pure crystalline 

 salt and dissolved it, adding at the same time to the 

 liquid some albuminoid matter, about one gramme to 

 100 grammes of the tartrate. The liquid placed in 

 a warm chamber fermented. During the process of 

 fermentation the liquid mass, previously limpid, be- 

 came gradually turbid, in consequence of the appear- 



