213 



ninm-racemate from solutions in the open air and in desiccators, 

 a preferential deposition of a little of the dextrogyratory salt was 

 repeatedly observed, probably under the influence of optically active 

 nuclei in the laboratory-dust. 



A systematic study of some of these phenomena was afterwards 

 made by Ostromisslensky 1 ), but especially in cases where the 

 racemic compound is not the stable one in comparison with the 

 mixture of the components. He observed, that an inactive solution of 

 right-, and left-handed sodium-ammonium-tarirates, if supersaturated, 

 and inoculated at 6 C. by a nucleus of fci'ogatory asparagine, will 

 deposit exclusively the dextrogyratory tartrate. Because Gernez 

 had already demonstrated that a supersaturated solution of the 

 dextrogyratory tartrate does not start to crystallise by inoculation 

 with a crystal of the left salt, Ostromisslensky concludes from 

 this experiment, that the laevogyratory asparagine is structurally 

 more closely related to the right-handed sodium-ammonium-tartrate, 

 than even the left-handed tartrate itself.. 



In the same way a preferential crystallisation of the dextrogyratory 

 component was observed ,if in this case as a nucleus of crystallisation 

 small quantities of potassium-tartrate, sodium-tartrate, and ammonium- 

 malate were used; the direction of the rotary power of the salt deposited, 

 appeared in all cases to be the same as that of the introduced nucleus. 

 Even the monoclinic ammonium-tartrate, which, however, according 

 to Pasteur 2 ), may also occasionally occur in a rhombic form, - 

 had the same effect ; therefore, it seems reasonable to suppose that 

 iso^'morphous substances can also produce the same effect. Most 

 remarkable is the fact, that substances which have no rotatory power 

 at all, may also be used as crystallisation-nuclei, and with the best 

 results, if only the inoculated crystal show a "non-superposable" 

 hemihedrism. 



Thus, from an inactive solution of asparagine, by the introduction 

 of a crystal of glycocoll'. CH 2 (NH 2 )COOH, the one component 

 was deposited in excess, although not in all experiments. Here again 

 is a wide field open for investigation. If we adopt the view of Ostro- 

 misslensky, that the crystals of glycocoll are really hemihedral, 

 these experiments seem to prove indisputably, that the enantiomor- 

 phous nucleus exercises an exclusive, directional force, perhaps 



*) I. Ostromisslensky, Ber. d. d. Chem. Ges., 41, 3035, (1908); Journ. 

 russ. phys. chem. Ges., 42, 102, 606, (1910). 

 2 ) L. Pasteur, Jahresber., (1854), p. 395. 



