THE OXIDATION PROCESS 205 



the view is held by some that peroxidases consist of these 

 metals in colloidal form. 



Peroxide and peroxidase form together a system known 

 as an oxygenase. The failure of oxidation of certain sub- 

 stances which sometimes occurs can only be explained by 

 supposing that different oxygenases exist for different 

 substances, the specificity applying to either component 

 of the system or to both. 



