-38- 



about in essentially the same way that is accomplished by phos- 

 phorus, benzaldehyde and other oxygen carriers." 



Hunger 51 states that the guaiac reaction is interfered with 

 by tannins, certain sugars, hydrogen sulphide, pyrogallol and 

 other reducing agents. 



Pozzi-Escof' 2 reports that when living tissues of animal or 

 vegetable origin do not affect guaiac, but decompose hydrogen 

 peroxide, that reductase must be looked for, which may be done 

 by treating them, out of contact with air, with a solution of in- 

 digo, or litmus, or ferric ferricyanide and note if any reduction 

 has taken place. They also liberate hydrogen sulphide from a 

 mixture of sulphur and potassium fluoride, if protected from the 

 air. 



Bach and Chodat 53 find that oxydase is always accompanied 

 by peroxydase, which they have found in about 25 plant families. 

 The oxydase has the power of forming peroxides in the presence 

 of free oxygen, which can be detected by the liberation of iodine 

 from hydriodic acid. When parts of plants containing these en- 

 zymes are heated to 80 C. the power to liberate iodine or color 

 guaiac blue is destroyed. This is also true of the expressed juice. 

 The power to liberate iodine disappears more quickly than that 

 which colors guaiac. When the substance ceases to act it may 

 be made active again by the addition of a small quantity of hydro- 

 gen peroxide. 



Bach 54 showed that a large number of substances when sub- 

 mitted to slow oxidation in the air, formed peroxides, and that 

 the peroxide formed helped to continue the oxidation. In the 

 blood the easily oxidizable substances first form peroxides and 

 these aid in the oxidation of the more difficultly oxidisable bodies. 

 The oxidation does not seem to be influenced by light. 



Wender 55 thought that the action of the oxydase in the living 

 cell is to cause the oxygen of the aeroxydase to oxidize the easily 

 oxidizable bodies so that intermediate bodies are formed, then 

 these are again decomposed by the action of catalase. The free 

 oxygen by the action of anaeroxydase (peroxides) becomes active 

 and oxidizes difficultly oxidizable substances. 



51 Ber. d. Bot. Ges. 19, 1901, p. 648. 

 62 Ann. Chem. anal. 7, 1902, 260. 



53 Ber. d. Chem. 35, 1902, p. 2466. 



54 Compt. rend. 124, 1897, p. 951. 



55 Chem. Zeit. 26, p. 1217 & 1221, 1902. 



