27 



The lacquer-work of the Japanese has long been a famous and 

 beautiful product of that country. The milky latex of the tree 

 Rhus vernicifera, rapidly oxidizes in a moist atmosphere to a 

 black lustrous varnish which is not attacked by any chemical 

 except concentrated nitric acid. In the latex Yoshida found a sub- 

 stance having the composition C14H18O2 which he called urushic 

 acid; besides this, he found a small amount of a nitrogenous 

 constituent, "a peculiar diastatic matter," which rapidly caused 

 the urushic acid to oxidize to the black oxyurushic acid (ChHisOs). 

 This peculiar diastatic matter of Yoshida lost its power to oxidize 

 urushic acid after being heated to 63°; so Yoshida thought it a 

 substance of enzymatic nature, which acted as an oxygen carrier 

 in these oxidations. 



Some years later, Bertrand® studied the lacquer formation more 

 carefully. He called the substance an oxidizing ferment, which 

 he believed brought about the oxidation of the mother-substance 

 of the black lacquer. He found that the ferment was destroyed 

 by boiling, and also that it was present in gum arabic and gum 

 Senegal, as well as in the latex of species of Rhus. He named this 

 ferment "laccase" and tested numerous plants for it, finding it 

 present in many cases. Bertrand used the tincture of guaiacum 

 as a test for laccase. 



In 1895, Bertrand with Bourquelot'^ tested a great many of the 

 higher fungi for laccase, using guaiacum as a reagent. They 

 found that laccase was widely distributed in these plants as well 

 as in those containing chlorophyll. They also investigated those 

 fungi which become colored when injured, and they believed the 

 phenomenon was caused by a ferment identical with laccase. Ber- 

 trand^ has shown that the oxidizing power of laccase is in some 

 way connected with the manganese present; for, by repeated pre- 

 cipitation with alcohol, he divided his laccase preparation into three 



s Bertrand. (a) Sur la latex de I'arbre a laque. Compt. Rend. Acad. Sci. 

 118: 1215. 1894. (&) Recherches sur le sue laiteux de I'arbre a laque du Tonkin. 

 Bull. Soc. Chim. [3], 11 : 717. 1894. 



^ Bertrand and Bourquelot. Laccase dans les champignons. Compt. Rend. 

 Soc. Biol. 47: 579. 1895. 



8 Bertrand. Sur Taction oxydante des sels manganeux et sur la constitution 

 chimique des oxydases. Compt. Rend. Acad. Sci. 124: 1355. 1897. 



