38 LOUIS PASTEUR 



Pasteur went to Vendome, obtained a sample of 

 the aspartic acid made by Dessaignes, and found, 

 as he had anticipated, that it possessed no rotary 

 power. The malic acid, which was made from the 

 aspartic acid was also optically inactive. Pasteur 

 concluded that there were four kinds of compounds 

 of identical composition, the symmetrical, the right- 

 handed, the left-handed and those arising from the 

 combination of right-handed and left-handed forms. 

 The artificial products were believed to differ from 

 the natural ones in being optically inactive. As 

 Pasteur says, "We recognize that when natural 

 organic bodies arise under the influence of vege- 

 table life, they are usually asymmetric in opposi- 

 tion to minerals and synthetical bodies. The ele- 

 mentary constituents of all living matter will as- 

 sume one or the other of the opposite asymmetries, 

 according as the mysterious life force, which causes 

 asymmetry in natural bodies, acts in one direction 

 or the other." 



The barrier, which Pasteur attempted to erect 

 between the products of the living and the non- 

 living, like so many others that have been erected, 

 has now broken down. The optically inactive 

 malic acid, which Pasteur derived from asparagin, 

 was subsequently shown by Bremer to be a com- 



