874 RESPIRATION AND OXIDATION. 



for example with the lecithins (THUNBERG, WARBERG and MEYERHOF l 

 as well as in the oxidation of certain thio-compounds. 2 



BATELLI and STERN 3 have made careful investigations as to the 

 occurrence of peroxidases in the animal organism. In order to eliminate 

 the action of catalases which are present in the tissues and which, 

 as shown by earlier investigators, decompose the hydrogen peroxide, 

 these experimenters used ethyl hydrogen peroxide, C2Hs.O.O.H, on 

 which the catalases do not act. With ethyl hydrogen peroxide and 

 hydroidic acid nearly all animal tissues gave the peroxidase reaction, 

 wherein free iodine was formed. SCHEUNERT, GRIMMER and ANDRYEWSKI 4 

 make use of the following solution as a reagent for peroxidases: 100 cc. 

 fresh tincture of guaiacum and 0.1 to 0.2 cc. 3 per cent H2O2 solution. 

 Blood does not give any blue coloration with this reagent, but in the pres- 

 ence of large quantities of H2O2 or other superoxide solutions (ethylhy- 

 drogen peroxide, oil of turpentine) it does give a blue coloration. With 

 this active tincture of guaiacum these experimenters were able to detect 

 peroxidases in the salivary glands, as well as the mucous membrane 

 of the stomach and intestine of certain varieties of animals. The liver 

 was always free from peroxidases. On the other hand, BATELLI and STERN 5 

 also tested the ability of various tissues of acting upon formic acid in the 

 presence of H202 with the evolution of carbon dioxide. In later works 

 these experimenters claim that in all animal tissues there exists a substance 

 of an unknown nature, the pnein, which has the ability of bringing about 

 the respiration in all animal tissues. Pnein, which is soluble in water, 

 dializable and resistant to temperature, increases the so-called chief respira- 

 tion, which is connected with the life of the cells and which stops more 

 or less rapidly after the death of the animal. The so-called accessory 

 respiration continues quite a long time after death, and this can continue 

 in the absence of cell elements and is of an enzymotic character. THUN- 

 BERG 6 , who has constructed an apparatus for measuring the respiratory 

 exchange of gas in small organs and organisms (microrespirometer) finds 

 that the salts of certain organic acids (succinic acid, citric acid, malic 

 acid, fumaric acid) accelerate more or less the gas exchange in surviv- 

 ing frog's muscles. In their last communication BATELLI and STERN 7 

 differentiate between two kinds of oxidation catalysts: the oxidases 

 and the oxidones. The first to which, among others the tyrosinase, alcohol- 



A Skand. Arch. f. Physiol., 24, 90 (1911); Zeitschr. f. physiol. Chem., 85, 412 (1913). 



1 Thunberg, Lunds Univ. Arsskr., N. F., 2, Bd. 9 (1913). 



Bioch. Zeitschr., 13, 44 (1908). 



4 /Wd., 53,300(1913). 



*Ibid., 21, 487 (1910); 30, 172 (1910); 33, 315 (1911). 



6 Skand. Arch. f. Physiol., 17, 23, 24, 25 (1911). 



T Bioch. Zeitschr., 46, 317, 343 (1912); Compt. rend., soc. biol., 74, 212 (1913). 



