216 



in Werner's paper 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. 



However, lately we succeeded to bring full evidence of a real 

 spontaneous fission in substances of this kind, in the case of potas- 

 sium-cobalti-oxalate. The transition-temperature was determined at 

 13, 2 C. : above this temperature the mixture of the two antipodes 

 is the stabler phase in contact with the saturated solution, while 

 below 13,2 C. it is the racemic compound, which is in stable equi- 

 librium with it 1 ). 



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, still appears a rather puzzling 

 problem in many points. A solution supersaturated with respect 

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

 a fortiori and appreciably more supersaturated with respect to the 

 mixture of the components, since the last are less soluble under the 

 existent conditions. 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 precipitation 

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

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

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

 fluence of the introduced nucleus acts on the supersaturated solution, 



J ) F. M. Jaeger, Proceed. Kon. Akad. v. Wet., 21, 702, (1918) ; Receuil des Trav. 

 des Chim. des Pays-Bas, 38, 171, (1919). 



