1534 
to prepare an isomeride thereof: 1st by repeatedly evaporating the 
acid with concentrated hydrochloric or hydrobromie acid; 2nd by 
fusion with potassium hydroxide. both methods, however, gave 
negative results; as could readily be expected there were formed, 
B-halogenglutaric acids, malonic and acetic acid, respectively. 
This also follows from my first communication ; it made no difference 
whether the compound started with was saponified with baryta, 
aqueous caustic potash or with hydrochloric acid. *) 
In the literature we find a number of communications concerning 
the conversion of the maleic acids into the more stable fumaric acids 
by treatment with purely chemical agents. *) So far as I am able 
to judge, the application of these methods does not cause any change 
in the glutaconic acid; hence, there is no sense in further discussing 
these methods here. 
CraMICIAN and Stiper*) could isolate from solid maleic acid that 
had been illuminated for 12 months, 12.5°/, of fumaric acid. This 
transformation also took place in aqueous solution; according to 
WisLicenus *) this reaction can be considerably accelerated by addition 
of a trace of bromine. 
The homologues of maleic acid are, according to the researches 
of Frrrig*) and otbers, converted exceedingly readily and rapidly 
into the correlated alkylfumarie acid, by illumination in an ether- 
chloroform solution after addition of a little bromine. 
Conversely, the stable isomerides can be converted into the labile 
(cis) modifications by illuminating in different solvents with ultra- 
violet light. *) 
I now thought it interesting enough to ascertain how glutaconic 
acid would behave in these photo-experiments. For this the following 
experiments were carried out’): 
1. A quantity of glutaconie acid was spread in a very thin layer 
on white glazed paper and, after covering with a glass plate illumi- 
nated for some months. Each month the melting point of a few 
specimens was taken ; after six months this was still totally unchanged. 
2. 1.5 gram of acid (m.p. 134—1386) dissolved in 30 ce. of water 
was illuminated in a tube of uviol-glass from 14 Sept. 1915 to 17 
1) Also compare Guruzerr and Botam: J. pr. (2) 54. 372 (1896) ; 58. 407 (1898). 
2) Compare Meyer-Jacopson I 2 p. 417—418 
5) Ber. 36. 4267 (1903). 
4) Ber. 29. R. 1080 (1896). 
5) Ann. 304. 119. 149 (1899). 
6) SroerMER. Ber. 42. 4870 (1909). 
7) I have again to heartily thank Dr. W. D. Couen for the assistance given 
during the execution of the two last experiments. 
