36. W. Gibbs on the Constitution of Organic Compounds. 
constitution of these acids, or in fact anything more than their 
ormation and modes of decomposition. Representing glyoxal 
CsH2Os« by the symbol gly, we have for the acids im question 
the following scheme. 
Glycolic acid, gly. H202. Glyoxylic acid, gly .O2. 
Malic acid, gly 2.H202. Anhyd. tartaric acid, gly 2.02 
Citric acid, gly 3. H202, 
Debus shows further how citric, malic and glycolic acids by 
losing two equivalents of water form aconitic and maleic acids, _ 
and glyoxal. Iam disposed to go much farther and represent 
the rational constitution of a number of organic acids by sup- 
posing them to contain glyoxal or diformoxyl, and formyl or di- 
formyl. It appears to me that it may reasonably be doubted 
whether the glycolic acid obtained by the action of nitrous acid 
upon glycosin is identical with that which Debus obtained by 
boiling glyoxal with milk of lime. I mean of course here to 
assume that ordinary glycosin may be formed by digesting formic 
aldehyd, C2HO2.H, with cyanhydric and chlorhydric acids, so 
_ that its structure is similar to that of alanin. There may be 
more than one species of glycosin, one being for instance 
N.CeHO2,C2H . H2 
Ht ¢O% 
while another is 
But bearing these distinctions in mind, I shall endeavor to give | 
rational formulas for certain organic acids involving as few as- 
sumptions as possible, and connecting those which are not ho- 
mologous. The formula (1.) which I have given for malic acid 
explains sufficiently well the products of its decomposition, since 
glyoxal by taking up two equivalents of hydrogen becomes — 
acetic acid, while the oxydation of C1H2O. or of CaH2 will § 
account for the formation of oxalic and carbonic acids. Maleic | 
and fumaric acids have the formula CsH«Os. If we suppose | 
that the action of heat simply splits the equivalent of glyoxal 
in malic acid into two equivalents of formoxyl, C2HO2, and 
that one eq. of formoxyl loses two eq. of oxygen, the formula | 
common to the two pyrogenic acids becomes a 
N.C#H202.H2 fe 
* H Oz. a 
2 
This formula gives no explanation of the difference between the 
two acids. It may be that, in one of these, two molecules 0 
formyl, C2H, are united to fosma molecule of diformyl, CsH:, 
but further researches are necessary before any satisfactory eX- 
planation can be proposed. 4 
