27 
According to Ostwald ( 317 ) Bach's theory of slow oxidation 
derives support from the energy relations existing between the com- 
bining substances and the intermediate and final products of the 
combustion. He (Ostwald) is also of the opinion that the production 
of unstable intermediate products is not be looked upon as an uncom- 
mon occurrence, but rather as the rule, and that as a general thing in 
chemical processes it is not the most stable products which are first 
produced, but ofttimes the most unstable. 
More recently Manchot and Herzog ( 282 > 283 ) have quantitatively 
studied the oxidation of indigo-white, hydrazobenzene, and a number 
of other complex organic compounds in alkaline solution, by air or 
oxygen. All of their results have gone to show that as much oxygen 
may be obtained from the metallic peroxides resulting from the oxida- 
tion as enters into the oxidation of the oxidizable compound itself- 
In other words, they found that one-half of the total oxygen consumed 
in such processes went to oxidize the autoxidizable substance, while 
the other half went to form hydrogen peroxide. ■ Thus in the case of 
hydrazobenzene we would have 
c 6 h 5 nh c 6 h 5 n 
I +0 2 = II -fll 2 0 2 . 
C 6 H 5 NH C 6 H 5 N 
As the oxygen molecule is composed of two atoms, he also reached 
the conclusion that a molecule of oxygen either united with the 
oxidizable substance to form a primary oxide, which is subsequently 
decomposed by water into a simpler oxide and hydrogen peroxide, 
or, as in the case of indigo- white, the molecule of oxygen unites with 
the hydrogen of the leuco-compound, forming indigo and hydrogen 
peroxide. If the oxidation take place in a solution of barium hy- 
droxide, the hydrogen peroxide is removed as fast as formed in the 
form of barium peroxide, equivalent amounts of indigo and barium 
peroxide being formed, thus: 
InH 2 + 0 2 + Ba(OH) 2 = In + Ba0 2 . + 2H 2 0. 
* 
In case the hydrogen peroxide is not removed in some insoluble 
combination, it reacts with a second molecule of indigo-white, in 
which case we would have ultimately two molecules of indigo formed, 
thus : ° 
7VtH 2 + 0 2 = In + H 2 0 2 , 
and 
InH 2 + H 2 0 2 = In + 2H 2 0. 
a Falk ( 170 ) in discussing the oxidation of indigo-white has offered the interesting 
and plausible suggestion that indigo-white may be looked upon as a phenol, which on 
oxidation passes to a qninone, thus: 
C - OH C - OH C : 0 C : 0 
C 6 H 4 / y>0 - cf >C 6 H 4 ► C 6 H 4 / >0 : c/ y>C 6 H 4 . 
X NH X NH NH XH 
