552 OXIDATION FERMENTS 



Jaquet, thereafter, in Schmiedeberg's laboratory, was 

 able to present evidence that even dead tissue, and in fact 

 tissue extracts devoid of cells, are capable of oxidizing alde- 

 hyde. A colorimetric method, based on the red color which 

 salicyclic acid gives with chloride of iron, was used in quan- 

 titative determination of the newly formed salicylic acid in 

 these studies. The distribution of aldehydases in animal 

 tissues was thereafter studied by a number of authors. 42 

 Martin Jacoby elaborated a procedure in F. Hofmeister's 

 laboratory which serves to separate aldehydases from pro- 

 teins by a combination of salting out, and precipitation by 

 alcohol and by uranylacetate. More recently Dony-Henault 

 and Mile, van Duuren 43 have submitted the problem of 

 aldehydases to a renewed study and have convinced them- 

 selves that there were many important technical errors in the 

 investigations of earlier authors. In order to avoid these, 

 separation of the salicylaldehyde from the salicylic acid 

 should be completed and the latter estimated, not by colori- 

 metry, but by gravimetric method (as tribromphenol). It 

 was found, moreover, in correspondence with the results of 

 Abelous and Aloy, 44 that oxidation of the aldehyde by the 

 "aldehydase" occurs best in the absence of free oxygen, 

 and that a given amount of the presumed enzymic solution 

 is able to oxidize only a definite amount of aldehyde. This 

 is clearly not an action like that of a catalysator, so much 

 so that the ferment nature of the aldehydases becomes de- 

 cidedly doubtful. Perhaps in this case, too, we are dealing 

 with the action of peroxides which are transferring their 

 oxygen to easily oxidizable substances. The lability of the 

 " aldehydases " would not interfere with such a view. 



Summary. The author deems it time, however, to lead 

 his readers out of the wilderness of academic discussion 



42 Salkowski and Yamagiwa, Abelous and Biarns, M. Jacoby, Resell, 

 Pfaundler, Zarichelli and others; cf. Literature: M. Jacoby, Ergebn. d. 

 Physiol., 1', 233-234, 1902; H. M. Vernon, ibid., 9, 214-216, 1910. 



43 O. Dony-H6nault and Mile. J. van Duuren, Bull. Acad. roy. Belg., 1901 ', 

 537; Arch, intern, de Physiol., 5, 39, 1907. 



44 J. E. Abelous and J. Aloy, C. R. Soc. de Biol., 56, 222, 1904. 



