258 



^ 14. In first instance it may be remarked in this connection, 

 that the expected iiemihedrism of the crystal-forms of tiie optically 

 active broimde and iodide investigated, does not manifest itself in 

 any distinct and convincing way, notwithstanding the enormous value 

 of the optical rotation of these salts. 



This fact is completely analogous to our previous experience in 

 the case of the corresponding cobalti-sahs. It proves once more that 

 even if Pasteur's principle be considered as principally correct, the 

 chemical identity of the dissymmetrically arranged substitutes must 

 be looked upon as a very unfavourable factor for the eventual mani- 

 festation of the hemihedrism predicted. These facts seem to sustain 

 our view previously explained, according to which the dissymme- 

 trical arrangement as such determines chietly the size of the optical 

 rotation of the molecule, while the chemical contrast between the 

 different substitutes is the predominant factor for the manifestation 

 of the crystallonomical enantiomorphism. 



Moreover, Wernej{ '), on the supposition, that analogously built 

 dissymmetrical molecules always should combine with the same 

 optically active radical into compounds showing analogous solubility- 

 relations, concluded that the laevogyrate Rho-saMs of the kind here 

 described, and the de.vtrogyrdte Co-salts would possess the same 

 stereometrica I configuration. 



For from the less soluble chloro-d-tartrates of both series, the 

 oppositely rotating Rlio-, resp. Cb-salts are set free, after the 

 d-tartaric acid has been removed from them. 



The Swiss scientist does not give sufficient and rational proof of 

 the correctness of his starting hypothesis'). On the contrary: the 

 solubility of chemical compounds is a constitutive property of so 

 highly a complicated nature, that there is every reason to doubt 

 a priori the general correctness of the supposition mentioned above. 

 Then, however, at the same time the value of Werner's 

 considerations, suggestive as they may be, has become appreciably 

 diminished, in so far as they concern the specific influence of the 

 central metal-atom on the direction of the optical rotation of the 

 molecule. 



As a counterpart of the views exposed by him, we therefore 

 wish here to bring forward the following arguments which, in our 

 opinion, appear to be founded on a firmer basis. 



^) A. Werner, loco cit. Berl. Ber. 45.1229 (1912i. Bull, de la Soc. Cliim. (1912), 

 p. 21; G. Urbain et A, Sénéchal, hitroduclion a I'Etude des Complexes, (1913), p. 174. 



~) Some cases are mentioned in his paper: however, there is no certainty that 

 really no inversion has occurred here during the experiment. 



