2. SUBSTANCES TAKING THE PLACE OF OXIDASE, PYBOGALLOL, AND 1402.
Inorganic substances which give light may be divided into three classes: (1) insoluble precipitates, (2) colloidal metals, (3) solutions of various salts. must always be added. The first two classes probably act as true inorganic catalyzers.
Among the group (2), a silver sol protected by protein so as to be fairly concentrated gave a good light. Concentrated Pt sol and Au sol also gave light. Colloidal and copper oxide gave nega tive results.
The following salts gave the best light in the concentrations indi cated: m/10 to m/20 m/100 m/50 (the light appears only after a long time), m/100 m/100 CrOs, m/10 The following gave no light: (m/10 to m/320), (m/10), K3Fe(CN)6 (m/10 to m/1000) (m/10), (2 per cent), (m/10), and bromine water. The mechanism of the action of these diverse substances will be considered in a subse quent paper.
Peroxide.—Only will give light with pyrogallol and an oxidase. benzoyl hydrogen peroxide, quinone, or ozonized turpen tine do not, although they give a strong guaiac reaction with the per oxidase of turnip-juice. We must also add to potato-juice, which already contains an organic peroxide whose oxygen may be transferred to guaiac. It is no doubt in too small a concentration to give light with pyrogallol.
Oxidizable substance.—Many of the amino- and hydroxy-phenols are rapidly oxidized by potato-juice but pyrogallol was the only one which gave light. The following were tried and all gave colored oxidation products: phenol, tricresol, pyrocatechin, resorcin, hydro chinon, orcinol, a-napthol, ortol, anilin, o and p toluidin, a-napthylamin, guaiacol, para-phenylen diamine, amidol, and pyramidon. Phloro glucin, B-napthol, and B-napthylamin were not oxidized.
Among the glucosides, vanillin, amygdalin, phloridizin, salicin, sapo nin, and esculin gave no light with potato-juice, either at 20° or 60° C.