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K. ASO. 



dilute alcohol (30%) for 40 hours. The filtrate was mixed with 

 strong alcohol {gz%) and left to stand for several days, where- 

 upon the precipitate was collected on an asbestos filter, dissolved 

 in a small quantity of water and again precipitated with strong- 

 alcohol . 



The product thus obtained from about 300 grams of the 

 fresh leaves was dissolved in 150 c.c. water, and subjected to the 

 following tests : 



A freshly prepared guaiacum tincture added to the cold 

 solution, gave at once a blue coloration, which soon increased in 

 intensity, while the boiled solution failed to do so. This proves 

 the presence of an oxidase. In order to observe the temperature 

 at which this enzyme is destroyed some tests were made with 



the following 



result : 





Temperature. 



Time of heating. 



Reaction with guaiac. 



72° C 

 75° C 

 76° C 



5 minutes, 

 n 

 ji 



Pale blue color after several seconds. 



A pale blue color set in after about 10 minutes. 



Slight coloration after about 13 minutes. 



We may therefore infer, tint the oxidase of the tea-leaves 

 is destroyed at about 76 0 — C. 



When tea-leaves are extracted directly with water, the 

 solution does not give the blue reaction, since the tannin in the 

 solution prevents it. 



In order to test also the presence of peroxidase in the tea- 

 leaves, I proceeded as follows : 



Fresh tea-leaves were finely crushed with addition of some 

 sand and extracted twice with strong alcohol (absolute) at the 

 ordinary temperature in order to remove the tannin, 1 since it 

 not only prevents the usual guaiac reaction of peroxidase, but in 

 smaller quantities can also bleach out again the blue color after 

 it has made its appearance. The residue was then extracted at 

 the ordinary temperature with water, and this solution 2 was 

 heated for 5 minutes at y6°C in order to destroy the oxidase. 

 In this liquid the peroxidase reaction was obtained with 



1 Not only the guaiac reaction of oxidase and peroxidase, but also the action of 

 my rosin and emulsin is prevented by tannin. (Reynolds Green : Fermentation, p. 154.) 



2 This solution produced a brownish coloration with hydroquinone. 



