1222 
$ 3. Evidently it must be considered of the highest importance 
to bring in this theoretically simplest case, — that namely where 
by the equality of the substitutes the “molecular dissymmetry” mani- 
fests itself only by the spacial arrangement of equal things, — the 
complete proof, that Pastrur’s principle is really right. It is 
therefore necessary to prove not only the optical activity of the 
antipodes obtained, but at the same time the ecrystallographical enan- 
tiomorphism of them. It was with this purpose, that the following 
investigations were made, and especially, because there are known 
cases, in which notwithstanding the clearly stated optical activity, 
an enantiomorpbism of the antipodes could not be proved with 
certainty, as e.g. in the case of lupeol’). 
According to Werner the enantiomorphism of these isomerides has 
been hitherto proved only in one single case: i.e with the potassiwm- 
salt of the rhodiumoralic acid: {Rho (C,O,),} K,; +1 H,O. These 
crystals however being, according to that author, triclinic, they must 
then evidently belong to the pedia/ class of that system, where „0 
symmetry at all is present. It is moreover well-known, that a number 
of substances in this class without any trace of optical activity, also 
crystallise ; [ myself described a very convincing instance of this kind 
some time ago with the (active diethylenediamine-diisorhodanato- 
(Ae), | 
(NCS), § 
its stereochemical configuration must undoubtedly be considered as 
a racemic compound of two enantiomorphic modifications. The occur- 
rence of this triclinic-pedial symmetry is therefore no a very favour- 
able circumstance for the convincing proof of the here discussed 
connection ; and it thus seemed necessary to give the desired erystal- 
lonomical proof in less doubtful cases and with substances showing 
a higher crystallographical symmetry. In what follows it will become 
clear, what has been the result of it. 
chromichloride: *) {Cr C7, a substance which on account of 
It may be again mentioned here, — before giving the detailed 
description of our objects in the next publication, — that Werner 
moreover succeeded recently in proving, that for the occurrence of 
the mirror-image-isomerism, the presence of carbon-atoms .in the 
molecule evidently is as little a necessary condition, as that of unsym- 
metric atoms in general. He was able to obtain the antipodes of the 
second class, whose number m is divisible by 4, can never be replaced by any 
combination of axes of the first class with a centre of symmetry, or with a 
plane of symmetry. 
') EF. M. JAEGER. Zeits. f. Kryst. 44. 568. (1908). 
*) EF. M. JAEGER. Zeits. f. Kryst. 89. 579. (1904). 
