Chemistry. — “On some Condensation-products of Aromatic Alde- 
hydes and Amines.” By Prof. F. M. Jageur. 
(Communicated at the meeting of May 29, 1920). 
$ 1. Although, according to Hantzscn’s and Werner’s theoretical 
views, the existence of stereoisomeric forms should be possible in the 
case of condensation-products of aromatic aldehydes and amines of 
‘the type: R,—CH = N—R,, yet it had appeared impossible during 
a long time to find with certainty’) cases of such isomerism with 
these so-called “bases of Scuirr’. In 1906, however, ANSELMINO”) 
described some eases, where substances of this kind were met with 
in two different crystalline modifications, which at the same time 
appeared to be strongly different in colour, being red and yellow. 
The author concluded from his investigations that no true 
dimorphism in the common sense of the word was present here, 
but that rather a chemical #somerism had to be supposed. The 
arguments brought to the fore by him for demonstrating that neither 
enantiotropic, nor monotropic relations whatsoever between the 
crystalforms of the red and yellow modifications of o-oxy-m-methyl 
benzylidene-aniline should be present, can, however, in our opinion 
hardly be estimated to be convincing. It seems notwithstanding this 
to be true, that the deviating chemical character of the yellow and 
the red forms, of which the last reacts much more easily with 
reagents attacking the HO-groups of the molecule, points in this 
case really to a chemical isomerism, in which to the red modification 
must then be attributed probably the ¢rans-configuration, in the sense 
of WeRNER’s theory. 
In the light of the interpretations given of the more recent in vesti- 
gations of crystals by means of RönrGurrays, the question about the 
discrimination between cases of “physical”, in contrast with “chemical” 
isomerism, seems to have no longer any real significance, at least 
for solid matter: undoubtedly each modification of polymorphous 
substances will in the solid state also possess a definite spatial con- 
figuration differing from that of the other modification ; and probably 
this difference will, at least partially, be preserved in the state of 
1) A. HantzscH and O. Scuwas, Ber. d. d. Chem. Gec., 34, 892, (1901). 
3) O. AnseLMINO, Ber. d. d Chem. Ges. 38, 3989, (1906); 40, 3465, (1907). 
