26 



In the last edition of Oppenheimer's "Die Fermente"^ he has 

 adopted the following classification of the plant oxidases, which 

 will be used in this paper : 



1. Laccase; phenolase, etc. 



2. Tyrosinase, melanin-forming enzymes. 



3. "Oxidases." 



(a) Oxygenase. 



(b) Peroxidase. 



4. Catalase. 



Laccase 



Schoenbein's interest in the problems of oxidation led him to 

 investigate the cause of the coloration of certain mushrooms, and 

 in 1856^ he published his results. In Boletus luridus he found 

 a substance soluble in alcohol that showed the same bluing from 

 injury of the fungus or on treatment with oxidizing agents in the 

 test-tube, that characterizes the bluing of the guaiac tincture; 

 moreover, the same substances decolorize this blued extract as 

 in the case of the blued guaiac tincture. Schoenbein saw the 

 importance of the fact that spontaneous bluing only took place 

 in the fungus itself, and concluded therefore that there was a 

 substance present in the fungus with power to greatly increase 

 the oxidizing power of the atmospheric oxygen. In Agaricus san- 

 guinareus he was also able to find the same sort of spontaneously 

 coloring substance that he noted in Boletus luridus. He con- 

 cluded that, besides the chromogenic substance of these fungi, 

 there is a substance present that can ozonize (activate) atmo- 

 spheric oxygen; he called such an activating substance a "Sauer- 

 stofferreger, " or literally an "oxygen-exciter." 



The first really careful work on oxidizing ferments was done by 

 Yoshida^ who, in 1883, investigated the chemistry of lacquer. 



3 Oppenheimer. Die Fermente und ihre Wirkungen, "Die Oxydasen, " chap. 7, 

 pp. 337-391. Spezielle Teil, 3d ed. 1909. Also for an excellent treatment of 

 oxidases in general see: 



Kastle. The Oxidases. Bull. 59. Hyg. Lab. U. S. Pub. Health and Mar. Hosp. 

 Serv. Washington, 1910. 



4 Schoenbein. Ueber die Selbstblauung einige Pilze, etc. Jour. Prakt. Chem. 

 67: 496. 1856. 



^Yoshida. Chemistry of Lacquer. Jour. Chem. Soc. 43: 472. 1883. 



