CHAPTER IX. 



PASTEUR'S LAW (continued). 



The Production of Racemic or Externally Compensated Sub- 

 stances from Inactive Materials. -- Chemical Reactions in which 

 Optically Active Substances take a Part. -- The Rotatory Power 

 of the Reaction-products in comparison with that of the original 

 Substances. The Wai den- Inversion: Facts, Problems, Explana- 

 tions. Reaction-velocity of Antipodes attacking Optically 

 Active or Inactive Substances. Artificial and Natural, or Sym- 

 metrical and Asymmetrical Synthesis. Production of Optically 

 Active Substances from Inactive Materials, influenced by other 

 Optically Active Substances. Partial and Complete Asymmetri- 

 cal Synthesis. The Final Problem. Experiments on Partial 

 Asymmetrical Synthesis. The Directional Influence of Asym- 

 metry or Dissymmetry, already existing, upon the Resulting 

 Dissymmetry of the Molecule. Asymmetrical Conditions during 

 Synthesis. Problems to be solved in Future. 



"Les produits artiftciels n'ont done aucune dissy metric 

 moleculaire] et je ne saurais indiquer I' existence d'une 

 separation plus profonde entre les produits nes sous 

 I' influence de la vie, et tous les autoes .... II y a la 

 des mysteres, qui preparent a I'avenir d'immenses 

 travaux et appellent des aujourd'hui les plus serieuses 

 meditations de la science''. 



L. Pasteur, 1860. 



1. In the preceding chapter we have already had occasion 

 ^to draw attention to the fact that special methods alone enable 

 us to obtain optically active substances from racemic compounds 

 or from externally compensated mixtures. Indeed, in all our 

 chemical reactions, as seen in our laboratories, we can only pro- 



