As the hæmoglobin does not lose this power on boiling, whereas luciferase does, the analogy is far from perfect. Many oxygen carriers are known, however, which may be destroyed on boiling their solutions, namely, the peroxidases of plant juices. Esculin will not luminesce with peroxidase and H_{2}O_{2}, but pyrogallol or gallic acid will. If one mixes a test tube containing pyrogallol solution + H_{2}O_{2} with potato or turnip juice or almost any plant extract, a yellowish luminescence appears. The plant extract loses the power to cause such luminescence on boiling and the peroxidase will not dialyze. It is, of course, comparable to luciferase and acts on the thermostable, dialyzable pyrogallol-H_{2}O_{2} mixture, which is comparable to luciferin. Curiously enough, although many hydroxyphenol and amino-phenol compounds can be oxidized by peroxidase and H_{2}O_{2}, only pyrogallol and gallic acid will oxidize with light production. Many other oxidizers can take the place of the peroxidase. A list of these is given on page 151. No other peroxide can take the place of H_{2}O_{2} with peroxidases as oxidizers, but a few can replace H_{2}O_{2} with other oxidizers. This is brought out in Table 7. TABLE 7 _Peroxides Giving Light with Pyrogallol and Oxidizers_ Key to column headings: [A]: Oxidizer. (Equal parts added to a mixture of M/100 pyrogallol and the peroxide) [B]: H_{2}O_{2} 3 per cent. [C]: Benzoyl hydrogen peroxide (insoluble powder) [D]: Ozonized turpentine (one drop) [E]: Na_{2}O_{2} (powder) [F]: BaO_{2} (powder) [G]: MnO_{2} (insoluble powder) [H]: PbO_{2} (insoluble powder) [I]: K persulfate M/10 [J]: Na perborate M/20 [K]: K perchlorate M/10 [L]: Quinone (insoluble crystals)