2 6o SCIENCE PROGRESS. 



of conveying the oxygen would, in Bertrand's opinion, be 

 discharged by the manganese, while the proteid matter 

 would give to the oxidase its other characters, such as are 

 made evident by the action of heat and the various reagents 

 used to identify it. 



Whether this hypothesis be accepted or not, it appears 

 from the experiments that laccase at any rate is much 

 assisted in its working by the presence of manganese, if it 

 is not entirely dependent upon its association with that 

 metal in some form. 



Besides the plants already mentioned laccase appears to 

 exist in a considerable number of fungi. In these plants 

 the phenomena of oxidation are very prominent, and in con- 

 sequence of this fact Bourquelot and Bertrand instituted in 

 1896 an investigation of them, with a view to ascertaining 

 whether laccase or some similar enzyme plays a part in their 

 metabolism (10). As in other cases, at the outset these ob- 

 servers laid considerable stress on the guaiacum reaction, 

 and they found that the liquid that can be expressed from 

 many fungi very rapidly oxidises the tincture with the 

 formation of a blue colour, but that it does not brino- 

 about this change if it is first boiled. The reactions of 

 the expressed juice with other bodies than tincture of 

 guaiacum leave no doubt that it contains the same 

 principle as the sap of the lacquer tree. It causes the 

 browning of the laccol prepared from the latex of Rhus ; 

 it yields crystals of purpurogalline when allowed to act 

 upon pyrogallol, produces quinone and quinhydrone from 

 hydroquinone, and gives a markedly brown colour with 

 gallic acid. 



The fungus which yields laccase most readily is RusstUa 

 fcctens Pers, one of the Basidiomycetes, which is fairly com- 

 mon in woods during the summer. 125 grammes of this 

 fungus, extracted with its own weight of chloroform water 

 yielded 60 cc. of a liquid which was at first pale yellow in 

 colour, but which gradually reddened on exposure to air. 

 When made to act on gallic acid in a closed flask which was 

 constantly shaken, it was found that the oxygen was gradu- 

 ally absorbed, 15 cc. disappearing during the first hour of 



