298 



antipode is decomposed more rapidly, when quinidine is the catalyst, 

 whereas the lefthanded antipode is on the contrary more readily 

 split up when, quinine is present in the solution. 



If the decomposition be stopped before complete fission of the 

 acid has been reached, the inactive acid originally used will show 

 an optical activity. 



When quinine was used as catalyst, in acetophcnone as a solvent, 

 the portion of the acid not yet decomposed had become dextro- 

 gyratory (an excess of 14% of the d-acid being present after a 

 heating for 168 minutes), while the camphor produced in this 

 reaction was laevogyratory. But if under the same circumstances 

 (75 C.) quinidine were used as catalyst, the unattacked acid 

 had after 186 minutes of heating become laevogyratory , while 

 the camphor appeared to be dextrogyrate. 



In these experiments the active bases are neither comsumed 

 in a detectable quantity, nor does there exist a stoechiometrical 

 relation between the quantities of the bases added and that of the 

 acid attacked; there is merely an accelerating influence, so that 

 the function is absolutely comparable with that of organic enzy- 

 mes or ferments. Indeed, here we have to deal with the complete 

 analogue of the action of the organic catalysts, and their remarkable 

 "specificity". 



B r e d i g and F i s k e treated benzaldehyde with HCN in the 

 presence of l-quinine or d-quinidine; the reaction took place in 

 chloroform as solvent. The base was removed by extracting the 

 solution by shaking it with 4-normal sulphuric acid, and the 

 mandelic acid thus obtained, when tested, appeared to be in reality 

 optically active. If the laevogyr&tory quinine were used as a 

 catalyst, the acid was dextrogymtory, whereas with the dextrogyrate 

 quinidine, it was found to be laevogyratory. These facts remove 

 all doubt as to the fact that the remaining traces of adhering 

 base canwo^ be the cause here of the optical activity observed. 



Since the experiments of Marckwald and Paul, which 

 are in some respects perhaps comparable with those mentioned here, 

 never has the remarkable analogy of specific enzyme-action, and 

 that of much more simply built catalysts such as quinine, quinidine, 

 etc., been brought to the fore in such a striking way. Beyond 

 all doubt we have to deal in both cases with the unequal velocities 

 of decomposition of the compounds formed intermediately between 

 the two antipodes and the accelerating, dissymmetrical catalysts. 



