210 



in Werner's figures are merely distorted triclinic crystals of the 

 racemic salt. From a theoretical point of view it would, moreover, be 

 quite incomprehensible that the more soluble crystals of the optically 

 active components should grow in- a solution of the less soluble 

 racemic compound, under conditions where the latter is obviously 

 perfectly stable. 



The possibility of a spontaneous fission of this salt can therefore 

 not be considered as proved by Werner's experiments, and still 

 remains an open question x ). 



6. As a result of all the investigations hitherto made on the 

 subject, we may say that the fact of the spontaneous fission of 

 racemoids into crystals of the optically active components, if recrys- 

 tallised from a suitable solvent, has been in many respects elucidated, 

 especially with respect to the part which the transition-temperature 

 has therein. But the behaviour of the supersaturated solutions in 

 contact with a nucleus of crystallisation, whether it be of a crystal 

 of one of the optically active components themselves or of an iso- 

 morphous or isodimorphous substance, appears a rather puzzling 

 problem yet in many points. A solution supersaturated with respect 

 to the racemate, is within the sphere of existence of the racemate, 

 a fortiori and appreciably more supersaturated with respect to the 

 mixture of the components. This may appear a fact which makes 

 it seem natural that a nucleus of one of the components, if introduced 

 into the supersaturated solution under these circumstances, will 

 provoke crystallisation; and something of an analogous character 

 may be imagined to take place in the case of the alcoholic precipita- 

 tion from aqueous solutions, as in Werner's experiments. But then 

 it remains entirely enigmatic still, why in such cases exclusively the 

 one component is deposited: the way in which this directional in- 

 fluence of the nucleus introduced acts on the supersaturated solution, 

 still remains wholly outside the scope of mechanical explanation. 



More, and rigorously systematical, observations and experiments 

 must be made, before the required insight into this problem can be 

 obtained. 



7. II. Fission of Racemoids by Combination with optically 

 active Substances. 



As a rule the method of fission dealt with in the preceding para- 

 graphs, does not lead to the desired result, because for some reason 



F. M. Jaeger, Chemisch Weekblad, Vol. 14, pag. 726. (1917). 



