FIEST DISCOVERIES. 21 



left-handed tartaric acid, with its truly surprising 

 properties, had been discovered ; molecular physics 

 and chemistry had been enriched with new facts and 

 theories of great value. 



The first care of Pasteur, after having discovered 

 the left-handed tartaric acid and the constitution of 

 paratartaric acid, was to compare very carefully the 

 properties of the new left-handed acid with those of the 

 right, endeavouring to determine by strict experiment 

 the influence on these properties of the internal 

 atomic arrangements of the two acids. Although we 

 are unable to picture the exact figure of these atomic 

 groupings, there can be no doubt that they are formed 

 of the same elementary particles, that they are, more- 

 over, dissymmetrical, and that, in short, the dissymme- 

 try of the one group is the same as that of the other, 

 but in an inverse sense. If, for example, the arrange- 

 ment of the atoms of the right-handed tartaric acid 

 present the exterior appearance of an irregular pyra- 

 mid, the arrangement of the atoms of the left-handed 

 tartaric acid ought, of necessity, to present the form 

 of a pyramid irregular in the inverse sense. 



II. 



Nominated assistant professor of chemistry at 

 Strasburg, Pasteur followed up with enthusiasm these 

 curious studies. To interrupt them for an instant it 



