FORMC ACID 
Bs 
58 
¢ 
BOTANICAL GAZETTE 
[JULY 
the colloidal platinum the electrolysis was carried out in two beakers 
connected by a siphon. ‘ 
D 
= 
15 
25 90 400 
SUNUTES 
Fic. 1.—Curves showing oxidation of formalde- 
hyde; lower curves OA, AB, BC represent succes- 
sive oxidations by platinum black which had been 
charged with oxygen by making it an anode in 
dilute acid at the beginning of each operation; 
upper curve OD represents the oxidation by hydro- 
gen peroxide in the presence of platinum black; 
ordinates represent amount of formic acid produced 
5M HCl r 
5 cc. of the mixture at the beginning of the 
ment and after a part of it had been neutralized by 
the So sig acid produced); abscissae represent time 
in minutes 
~Tt was s 
removed by boiling the tincture with animal charco. 
After this treatment with active hydrogen, the plati- 
num crucible, when placed in a solution of gum guaiac” 
free from peroxide, or in:a solution of potassium iodide, 
produced no oxidation. But after subjecting the colloidal 
metal to active oxygen (by making it the anode in the 
same electrolysis apparatus as used before) it produced rapid 
oxidation when placed in 
a solution of either gum 
guaiac or potassium 
iodide. This was shown 
by the appearance of a 
blue color in the former | 
and after the addition of 
starch paste in the lat- 
ter. Although this reac- 
tion took place rapidly, 
it was observed that 
only a very small 
amount of material was 
oxidized. This sug- 
gested that the amount 
of oxygen taken up by 
the platinum was suffi- 
cient for only a limited 
oxidation. 
To determine whether 
this was true, quantita- 
tive experiments were 
undertaken. 
purpose the oxidation of 
formic aldehyde to for- 
mic acid suggested itself 
as a reaction, which is 
shown by Moore and WuitLey (Biochem. Jour. 4:169) that ordinary 
alcoholic solutions of gum guaiac frequently contain traces 
al. 
of peroxide which may be 
