230 



Papers from the Department of Marine Biology. 



The concentration of acid and alkali added give, of course, no idea 

 of the H-ion concentration in the potato-juice. The oxidase acts best 

 in the region of neutrality or slight alkalinity, and Reed (40) finds by 

 hydrogen electrode measurements that the oxidase of potato is inhib- 

 ited in a ChI.oXIO"^. The effect of the acid is reversible unless it 

 has acted too long. 



Note from table 24 that KCN affects the pyrogallol peroxidase in 

 very weak concentration (m/2,000), but is not so effective in destroying 

 catalase or preventing the bluing of guaiac. NaOH and HCl are not 

 so toxic. As we might expect, the HCl is the more toxic of the two. 



5. Effect of Fat-Solvent Anesthetics. 



Saturation of the potato-juice or blood with ether or chloroform does 

 not affect its power to produce light with pyrogallol + H2O2. A sam- 

 ple of horseradish-root extract preserved 45 days under ether gave a 

 good light when mixed with pyrogallol + H2O2. 



6. Is the Oxidase a Catalyzer? 



That oxidases in general are not catalyzers, but are used up in the 

 reaction has been proven by the work of Kastle (16), who found that 

 the amount of phenolphthalein oxidized is proportional to the quantity 

 of blood present, and of Bach and Chodat (41 and 42), who found that 

 the amount of pyrogallol oxidized to purpurogallin is proportional to 

 the amount of peroxidase and also to the amount of H2O2 present, 



