283 



central atom, however, appears to be also of predominant signifi- 

 cance therein. 



5). The non-superposable hemihedrism of the two antipodes in 

 the crystalline state, as postulated by Pasteur, is a phenomenon- 

 which in most cases runs parallel to the occurrence of optical 

 rotatory power, but it is not always necessarily manifested 

 with it. It is undeniable, that there is often a parallelism between 

 the two phenomena, but sometimes it may seem that there is no 

 such parallelism. The . degree of non-superposable hemihedrism 

 seems to be chiefly dominated by the chemical contrasts between 

 the different substitutes, and perhaps has only an indirect relation 

 to the absolute magnitude of the optical rotatory power as 

 exhibited by the molecule in the dissolved state. 



6). The general agreement between experience and theoretical 

 deduction as founded on the conceptions of Van 'tHoff and 

 Le Bel's theory regarding the stereometrical configuration of 

 the atoms in the molecules, proves that these stereometrical 

 formulae are not merely rough schemes, but that they even give 

 a fairly exact idea of the really existing geometrical relations in 

 such molecules, especially with respect to their configuration in space. 



In the following chapter some other problems intimately con- 

 nected with Pasteur's law will be considered more in detail. 



