OXYGEN SUPPLY OF CERTAIN ANIMALS 311 



bottom of Lake Mendota where these plant fragments are 

 abundant during the stagnation period. Consequently, this 

 oxidizing agent must be present in plant tissues under such 

 conditions. It would seem that this oxidizing substance was 

 not something which was being stored, but was rather a substance 

 which was continually being formed, inasmuch as plant frag- 

 ments treated with guaiacum could later have the blue color 

 washed out with alcohol and would again be capable of oxidizing 

 fresh guaiacum. 



The question again arises, is this substance which is found in 

 the disintegrating plants and which is capable of oxidizing 

 guaiacum atomic oxygen, or is it some other oxidizing agent? 

 The following experiments, although they do not prove that this 

 oxidizing substance is atomic oxygen, j^et indicate that such is 

 the case. The plant fragments found in the mud will oxidize 

 guaiacum without the addition of hydrogen peroxide. Frag- 

 ments boiled for a short period will not oxidize guaiacum unless 

 hydrogen peroxide is added. As hydrogen peroxide has no 

 effect on guaiacum, this seems to indicate that boiling destroyed 

 a peroxide component of an enzyme complex in the plant tissues, 

 for it did not destroy a substance capable of splitting atomic 

 oxygen from hydrogen peroxide which then oxidized guaiacum. 

 Active oxygen is the only oxidizing substance which can be split 

 from hydrogen peroxide. It there foreseems probable that the 

 enzyme-like substance, not killed by boiling, was in the unboiled 

 plant fragments splitting off atomic oxygen from a naturally 

 occurring peroxide. It was also shown by experiment that 

 boiled plant tissues were capable of splitting off active oxygen 

 from hydrogen peroxide and of oxidizing guaiacum in the absence 

 of molecular oxygen and light. 



Since the results were found to be constant regardless of when 

 or where the experiment was performed, it follows that this 

 oxidizing substance is constantly being liberated by the decaying 

 plant remains on the bottom of Lake Mendota. If this oxidizing 

 substance is atomic oxygen, then here is a source of oxygen for 

 the animals which live there during the stagnated period. The 

 amount of ox3^gen given off at any one time would be very small,, 



