The Role of Dissymmetry 79 



that resolution had taken place, the crystals, dissolved in chloroform, had a 

 rotation of +27° while that of the mother hquor was —0-15°. 



On crystallization of racemic histidine hydrochloride Duschinsky [39] obtained 

 the (+)-isomer while Vogler & Kofer [40] were the first to resolve 2 : 4-dioxo- 

 3-diethyl-5-methylpiperidine into its antipodes. 



Recently, Darmois [41] has proposed a general method for the resolution of 

 racemic bases, based on the artificial forcing of spontaneous crystallization. 



By this method Ferreira [42] made a partial resolution of the racemic alkaloids 

 narcotine and laudanosine which are not soluble in water. He converted them to 

 hydrochlorides and caused pyridine to react slowly with the solution. The 

 resolution of synthetic adrenaline was considerably more successful. After four 

 crystallizations the alkaloid was almost completely resolved [41]. 



It is obvious from the material which has been surveyed, that it is essentially 

 compounds of comparatively simple structure which can be submitted to 

 spontaneous separation. Therefore, as has been shown above, it seems hardly 

 likely that the primaeval colloidal organic substances became dissymmetrical in 

 this way. On the contrary, the behef that the only factors playing a part in bringing 

 about the primary asymmetry of the organic world were asymmetric adsorption 

 and catalysis [43] and circularly polarized Ught, polarized mainly in one direction, 

 meets with no such difficulties and agrees with the experimental evidence [44]. 



PHOTOCHEMICAL ASYMMETRIC SYNTHESIS 



Interest in the question of the ways in which the primary dissymmetrical 

 substances could have arisen has increased rapidly since the discovery of the 

 optical isomer by reducing phenylglyoxylic acid, by adding bromine to stilbene 

 and esters of fumaric or cinnamic acids [46-49]. 



Pasteur [45] saw physical processes as the source of the optical activity of 

 the substances important for life. 



To test this idea he tried to bring about an absolute asymmetric synthesis by 

 crystallizing the antipodes out of a racemate in powerful magnetic fields or in 

 rapidly rotating tubes. 



Under similar conditions attempts have been made to obtain an excess of one 

 optical isomer by reducing phenylglyoxylic acid, by adding bromine to stilbene 

 and esters of fumaric or cinnamic acids [46-49]. 



Similarly, electrolysis of salts of iron with substituted malonic acids in a 

 magnetic field did not lead to the formation of optically active products [50], 

 although the influence of a magnetic field in orienting crystals of complex salts 

 of cobalt, nickel [51, 52] etc. has been noticed. 



The attempts by Ostromyslenskii [53] to find differences in the rates of 

 crystallization of antipodes were unsuccessful. So were those of Rosenthaler 

 [54] to hydrolyse polysaccharides asymmetrically in a magnetic field. 



All these unsuccessful attempts were based on the false assumption that a 

 magnetic field, or mechanical movement, were factors of such a nature that their 



