41 



hydrogen peroxide as Catalase, or oxydize pyrogallol as Oxy- 

 genase ; or liquefy starch paste, forming substances which de- 

 duce Fehling's solution, as Amylase; or invert cane sugar, as 

 Invertase ; or break up glucosides, as Emulsin ; or digest coagu- 

 lated albumen, as the Proteolytic enzymes. 



Chodat and Bach" state that Bertrand found that, by frac- 

 tional precipitation of laccase with alcohol, he obtained a 

 substance poor in manganese and weak in oxidizing power, also 

 a substance rich in manganese and strong in oxidizing action, 

 but did not suspect that the decrease in power of oxidation was 

 connected with the separation of peroxydase. Five years later 

 fractional precipitation was brought forward as a method of sepa- 

 ration of peroxydase from oxydase, by Aso. M 



The authors have used this method to obtain two end frac- 

 tions, one with weak oxidizing power and the other without any 

 oxidizing action. The first was practically insoluble in 40% alco- 

 hol while the other was soluble, and was active with hydrogen 

 peroxide, and behaved as a true peroxydase. The weak oxidizing 

 fraction which principally took the part of an oxygen carrier 

 they designate as Oxygenase. They add that it is comparatively 

 easy to prepare peroxydase free from oxygenase, but have not 

 succeeded in preparing oxygenase free from peroxydase. A par- 

 tial separation may be made by extracting a mixture of the two 

 with 30 to 60 per cent, alcohol, or by dialysis with pure water 

 when the peroxydase passes into the dialysate. 67 



In 1892 Tschirch 68 called attention to the fact that the differ- 

 ence between the color of black and green tea was due to fer- 

 mentation. The black tea is prepared by allowing the fresh leaves 

 to undergo partial fermentation at a relatively low temperature, 

 while in the case of green tea the ferment is destroyed by heat. 



Aso 69 states that the color of black tea is produced by the 

 action of oxydase on the tannin in the first stage of preparation, 

 while in the green tea the ferment is destroyed. 



Tschirch and Oesterle 70 state that the formation of cola-red 



co Ber. d. Chem. 36, 606, 1903. 

 50 Bull. Coll. Agric. Tokio, 5, 2, 1902, p. 233. 



67 Compare Engler and Wild, Ueber die sogenannte activirung des 

 Sanerstofrs und iiber Superoxyd bildung. Ber. d. Chem. 30, 1669, 1897. 

 m Indische Heil-und Nutzpflanzen und deren Kultur, Berlin, 1892. 

 " Bull. Coll. Agric., Tokio, 4, p. 254, 1901. 

 " Anatom. Atlas d. Pharmacognosie, p. 350. 



