1536 
formation of compounds wherein carbon-combined mercury occurred 
(for instance, a//locinnamic-, maleic-, citraconic- and itaconie acid). The 
way the mercury is combined may be typified as follows: 
GOE — C— OH 
| +| — (X = O.COCH,) 
—C HgX —C—Hex 
| | 
Most of the isolated compounds had, however, a more complicated 
structure; so for instance the HgX-residue has frequently entered 
into reaction with an adjacent carboxyl group : 
—C — OH 
| + XH 
—C — Heg 
| | 
CO —O 
The correctness of these formulae is also shown by the fact that 
these Hg-compounds, when decomposed with hydrogen sulphide, do 
not yield the original unsaturated acids, but a g-oxyacid. 
The complex salts of the above dibasic acids all contain, however, 
also normally combined mercury. 
It was now suspected that the normal glutaconic acid would react 
with mercuric acetate with formation of complex salts as there exists 
here the possibility of a transformation into a “labile” c7s-modifi- 
cation, before the real reaction takes place. This suspicion proved 
to be correct. 
To a warm solution of 5 grams of glutaeonie acid in 50 ec. of 
water a solution of 7.5 grams of mercuric acetate in 300 ce. of 
water was slowly dropped. After 12 hours the precipitate formed 
was collected at the pump, washed with water containing some acetic 
acid, then with alcohol and ether and finally dried in vacuum over 
phosphorus pentoxide, (Preparation I). 
To the warm filtrate 10 grams of Hg-acetate dissolved in 100 ec. 
of water was once more added. The precipitate formed was now at 
once collected and treated as before. (Preparation II). 
Both specimens are white powders insoluble in water ; they dissolve, 
after ar temporary yellow coloration, without any separation of mer- 
curie oxide in dilute alkali and thus contain exclusively complea- 
combined mercury. Just like the compounds obtained by BrrrMANN 
they are soluble with a fairly neutral reaction in potassium chloride 
and with a faint alkaline reaction in potassium iodide solution. 
The mercury determination gave the following results: 
