59 
all be capable of activating ox} T gen toward guaiacum, hydroquinone, 
etc. F rom what is known regarding the effect of manganese onlaccase, 
it would seem that almost any colloidal solution of manganese might 
exhibit essentially the same reactions as laccase. (Seepp. 122-131.) 
The conduct of the oxidases and peroxidases toward a large number 
of substances has been investigated by Bertrand, and also by Bour- 
quelot and others. In this connection Bertrand ( 52 ) has studied the 
influence of the chemical constitution of certain organic compounds 
on their oxidizability by laccase. 
Thus, he has shown that the oxidizability of the polyatomic phenols 
by laccase depends upon the relative ease with which they are con- 
verted into quinones. In this respect they conform in general to the 
findings of the Brothers Lumiere ( 279 ) respecting the action of such 
substances as photographic developers. Thus, para-amido-phenol is 
an excellent developer and is also readily oxidizable by laccase, 
whereas meta-amido-phenol is not. a photographic developer and is 
not acted upon by laccase. Similar results have been obtained with 
para-phenylene diamin and meta-phenylene cliamin. On the other 
hand, the aromatic monophenols and monamins are not as a rule 
easily oxidized by laccase; the only substances easily oxidized by 
laccase are those of the benzene series containing hydroxyl or amino 
groups in the ortho or para positions. This rule defines the oxidizing 
power of laccase and serves to distinguish this soluble oxidizing fer- 
ment from the oxidases which attack compounds of different chemi- 
cal constitution. 
Bourquelot ( 74 ) has also investigated the action of the oxidizing 
ferments found in Russula delica , namely, laccase and tyrosinase, on 
a large number of compounds. He found the oxidizing power of this 
mixture of oxidases to be dependent upon the reaction of the medium. 
Thus, a solution of anilin was scarcely oxidized at all, owing to its 
alkalinity, while in the presence of small amounts of acetic acid the 
oxidation proceeded rapidly up to a certain limit of acidity, beyond 
which it was again checked, owing to the presence of an excess of acid. 
He found that the mixture of oxidizing ferments from Russula delica 
is capable of oxidizing a large number of phenols ( 77, 79 ) and aromatic 
amino compounds ( 82 ), among which may be mentioned phenol, the 
cresols, xylenols, thymol and carvacrol, alpha- and beta-naphthol, 
also the ethers of various phenols ( 79 ), anisol, phenetol, guaiacol, acetyl- 
guaiacol, veretrol, eugenol, acetyl-eugenol, vanillin, and vanillic acid; 
and by means of aqueous extracts of Russula delica and Lactarius 
velutinus he was able to obtain powerful oxidations with anilin, 
sulfate of anilin, methyl-, ethyl-, and diethy-anilin, met a- and para- 
toluidin, the xylidins, naphthylamin, and veratrylamin. 
According to Bertrand and Bourquelot ( 64? 78 ) tvrosin is the best 
reagent for tyrosinase. 
