ALDEHYDASES 551 



method for the determination of indophenoloxidase in ani- 

 mal tissues. His results indicate that those mammalian tis- 

 sues, which, according to Ehrlich, are highly saturated with 

 oxygen, and fail to change indophenol blue when injected 

 intra vitam (as the muscle of the heart, tongue and dia- 

 phragm) are apparently rich in oxidases. On the other 

 hand, tissues which reduce intra vitam indophenol blue to 

 indophenol white (as the glands and the bulk of the striated 

 and smooth muscles) prove to be much poorer in oxidase. 

 The richness of the tissues in oxidases, therefore, runs 

 parallel with the grade of their saturation with oxygen ; and 

 the idea necessarily arises that we may be dealing with a 

 storage of oxygen in the form of organic peroxides or l ' oxy- 

 genases." Should this suspicion prove correct this reac- 

 tion will serve as a test for oxygenases. Indophenol blue 

 synthesis fails notably in the tissues of animals which have 

 been killed by potassium cyanide (a frank "ferment 

 poison"). 41 



Purin Oxidases. Another well defined group of oxidiz- 

 ing ferments is composed of the purin oxidases. These are 

 ferments concerned in the physiologically important oxida- 

 tion catabolism of the purin bases into uric acid and of this 

 latter into allantoin. The most important information we 

 possess of this subject was presented in earlier parts of these 

 lectures (Vol. I of this series, p. 112, Chemistry of the Tis- 

 sues; vide supra, p. 149) and need not be further dealt with 

 here. 



Aldehydases. While the requirements of historical jus- 

 tice would forbid that the " aldehydases " be passed in 

 silence we here come nevertheless into a comparatively un- 

 known field. 0. Schmiedeberg originally discovered that if 

 arterialized blood be perfused through a fresh liver or lung 

 and salicylaldehyde be added, salicylic acid is formed to 

 some extent. 



40 H. M. Vernon (Oxford), Jour, of Physiol., 42, 402, 1911; 43, 96, 1911; 

 44, 150, 1912. 



41 H. Raubitschek ( Czernowitz ) , Wiener klin. Wochenschr., 1912, 149. 



