FIRST DISCOVERIES. 31 



to be hoped for.' He never spoke of these attempts, 

 because he had not had the time to follow them to 

 the issues of which he dreamed; but to this day 

 he remains persuaded that the barrier which exists 

 between the mineral and organic kingdoms and 

 which is revealed to our eyes by the impossibility of 

 producing, in the reactions of the laboratory, dissym- 

 metric organic substances can never be crossed until 

 we have succeeded in introducing among these re- 

 actions influences of the dissymmetric order. Accord- 

 ing to Pasteur, success in this direction would give 

 access to a new world of substances, and probably also 

 of organic transformations. As we have succeeded 

 in finding the inverse of right-handed tartaric acid, 

 we may hope to obtain some day all the immediate 

 principles inverse to those now known to us. Who 

 could say what vegetable and animal species would 

 become if it were possible to replace, in the living 

 cells, cellulose, albumen, and their congeners, by their 

 isomers with an inverse action ? Certainly the thing 

 is not easy, and Pasteur would be the last person to 

 deceive himself as to the difficulty of the problem. His 

 latest thought on the matter is this : When the 

 attempt is made to introduce into living species pri- 

 mordial substances, inverse to those now existing, the 

 great difficulty will be to master the tendency (devenir } ) 



1 [M. Pasteur appears to use the word devenir as a substantive 

 in a sense equivalent to the German Werdcnde.'] 



