262 SCIENCE PROGRESS 



contain oxidase. I knee the method of estimating the oxidasic 

 power of the tissues employed by Battelli and Stern ' may 

 ultimately prove the best one, though it has fallacies of its 

 own. These investigators found that minced tissues have the 

 power of oxidising succinic acid, C 4 H 6 4 , to malic acid, C 4 H 6 8 , 

 with the absorption of molecular oxygen, and that as a rule 

 the volumes of oxygen so absorbed closely correspond with 

 those taken up by the tissues when mixed with />-pheny- 

 lenediamine. This substance is probably oxidised in the same 

 way as the indophenol reagent, and many of Battelli and Stern's 

 determinations of oxygen absorption by various tissues show 

 a rough correspondence with my estimations of indophenol 

 formation : but some tissues, especially liver and skeletal 

 muscle, show relatively much greater absorption of oxygen 

 than production of indophenol, probably because they are 

 specially rich in reducing substances. 



At the same time it is doubtful how far the oxygen 

 absorption of a minced tissue is a true measure of its oxidase 

 content. For instance, Battelli and Stern found that minced 

 brain, when mixed with ^-phenylenediamine, absorbed two or 

 three times more oxygen than when mixed with succinic acid, 

 or to quote actual figures, ioo gm. of dog's brain when mixed 

 with diamine absorbed 225 c.c. of oxygen in half an hour at 

 39 C, but when mixed with succinic acid absorbed only 85 c.c. 

 Is this difference due to the presence of different and specific 

 oxidases for each of the two substances, or is it due to the 

 occurrence of oxidation processes other than that produced by 

 oxidase action? It seems more probable that such additional 

 oxidation processes do occur, and that one and the same oxidase 

 is responsible for both these oxidations and for that of the 

 indophenol reagent, for the oxidase of all these substances is 

 quite insoluble in water or saline, and it is so thermolabile 

 as to be entirely destroyed in half an hour at 6o° C. 2 According 

 to Battelli and Stern the oxidase is a single enzyme, and not 

 comparable to the oxygenase + peroxidase of vegetable tissues. 

 In any case the soluble peroxidase described above takes no 

 part in its activities, but it is possible that it consists of an 

 insoluble peroxidase bound up with an insoluble oxygenase. 



1 Battelli and Stern, Biochem. Zeit. 30, p. 172, 1910; 46, pp. 317 and 343, 1912. 

 s Vernon, Journ. Physiol. 44, p. 152, 191 2 ; Battelli and Stern, Biochem. Zeit. 

 46, p. 343, 1912. 



