SOURCES OF ENERGY IN ANAEROBIOSIS 197 



breakdowai. Since these animals do not metabolize fat 

 (von Brand, 1934a, 1941), one can hardly escape the con- 

 clusion that proteins play a role in energy production. 



The very curious findings of Harnisch (1938) deserve 

 mention here. He exposed larvae of Chironomus thum- 

 mi to starvation under anaerobic conditions and found 

 that the nitrogen content of their bodies, as determined by 

 Kjeldahl's method, increased. Since a nitrogen fixation is 

 very unlikely, Harnisch assumes that nitrogenous sub- 

 stances which, before deprivation of oxygen, could not be 

 determined by Kjeldahlization were transformed during 

 the period of oxygen deprivation so as to become demon- 

 strable by that procedure. He also suggests that these 

 processes might liberate oxygen which then, of course, 

 could be used for energy-producing aerobic oxidations. 

 If this is so, the anaerobic protein metabolism would 

 serve, in an indirect manner, to produce energy. It 

 should be emphasized, however, that Harnisch performed 

 only two experiments. A reinvestigation based on more 

 material is desirable before these findings, which Har- 

 nisch himself designates as only preliminary in nature, 

 can be accepted as facts. 



