262 EXISTENCE OF A REDUCING ENDO-ENZYME 



C. A. HERTER(^)in 1904 and 1905 published two papers on 

 the reducing powers of living tissues. He injected methylene 

 blue intra vitam. He stated that "the liver usually retains a 

 high grade of reducing activity for several hours after death." 

 He found lung, suprarenal capsule and grey matter of central 

 nervous system all reduced the blue to the leuco state. An 

 animal which was chilled by wet cloths or ice "exhibited the 

 powers of reduction much diminished by cold". Herter 

 showed that, conversely, the reducing powef of the tissues of an 

 animal injected with the micro-organisms of a specific fever 

 was increased. 



Underbill and Closson 0°) in 1905 confirmed Herter's 

 views and came to the conclusion that their experiments 

 demonstrated the simultaneous action of both oxidative and 

 reducing processes in the animal organism. 



In 1906 Professor J. C. Irvine and I(^^)showed that the 

 intra vitam reduction of Prussian blue was not a deoxidation, 

 but the removal of an ionic charge. 



By perfusing the surviving kidney of a sheep with the 

 Prussian blue mixture, I obtained from the ureter an abso- 

 lutely colourless artificial urine which was blued immediately 

 on treatment with H2 O2. 



Authors with increasing frequency are recognizing the 

 existence of reductase. 



Oppenheimer (}^), for instance in his large work on "Fer- 

 ments" does so: most of the authors of text-books mention 

 the reducing power of tissues even when they do not recognize 

 "reductase". 



Some, however, frankly postulate a reducing ferment; 

 thus, G. P. Mudge(^^) writes, "If an albino does carry a 

 chromogenous body which only needs the influence of an 

 oxidizing or reducing ferment to cause it to produce pigment", 

 etc. 



