308 ARCH E. COLE 



at the bottom of Lake Mendota and the fact that for a portion 

 of each year the water in which the larvae Hve contains no 

 dissolved oxygen. If in the apple there is present an enzyme 

 which can build up a peroxide by obtaining extra atoms of 

 oxygen from the molecular oxygen in the air, may not the enzyme 

 complex in the chironomid larvae have the ability to build up a 

 peroxide by obtaining its extra atom of oxygen from some other 

 substance contained in the water or mud? If such a peroxide were 

 thus formed, the oxygen would be split from it by the peroxi- 

 dase-like substance in the blood, and so be carried by the haemo- 

 globin to the tissues where it could be utilized in physiological 

 oxidation. Should this be the case, we have here, then, a system 

 which would be slowly yet surely releasing oxygen for the oxi- 

 dative processes which go on within the organism at the time 

 when the supply of oxygen from the surrounding water fails. 

 If this reaction can be shown to proceed when there is no oxygen 

 in the surrounding medium, then we have an explanation for 

 the source of oxygen used by the chironomid larvae during the 

 stagnation period. 



Experiments were made to test this hypothesis. (For appa- 

 ratus and description of the experiment, see Appendix, p. 319.) 

 It was found, however, when the molecular oxygen had been, 

 removed both from the liquids involved and the atmosphere 

 above them, that the enzyme complex was not capable of oxi- 

 dizing the guaiacum. This, of course, would indicate that 

 molecular oxygen was necessary in order to build up the peroxide 

 component of the complex, as is true in the case of the enzyme 

 complex found in the apple; and inasmuch as oxygen is not 

 present during the stagnation period at the bottom of the lake 

 where the chironomid larvae live, such a mechanism would mean 

 nothing. 



However, there are some points which must be taken into 

 consideration here. Perhaps the concentration of carbon dioxide 

 or nitrogen which was used to take the place of the oxygen- 

 bearing atmosphere had an inhibiting effect on the action of 

 the enzyme, or perhaps certain constituents were lacking which 

 were necessary for the functioning of the enzymes; in other words 

 that the exact substrate for the enzj'me was not present. 



