256 ^LAIMARY 



2. The oxygen debt incurred under anaerobic condi- 

 tions is usually repaid upon readmission of air. The ex- 

 tent of the repayment is different in various species, de- 

 pending on the chemical nature of the recovery processes 

 and also on whether or not non-oxidized substances were 

 excreted during the anoxic period. 



3. Carbon dioxide is very frequently retained during 

 recovery and is used in the resynthesis of bicarbonates 

 that had been decomposed in the preceding anaerobic 

 processes. This usually leads to abnormally low respira- 

 tory quotients at least during the initial stages of recov- 

 ery. 



4. The chemical nature of the recovery reactions ap- 

 pears to be more diversified in invertebrates than in ver- 

 tebrates. Carbohydrate resynthesis has been observed 

 in worms and insects, but this phenomenon is, in most 

 cases, less pronounced than in vertebrate muscle. In 

 other invertebrates, especially in insects, a much greater 

 proportion of the accumulated end products, sometimes 

 even all of them, are oxidized and no resynthesis of gly- 

 cogen takes place. 



5. The data on the nitrogen metabolism of inverte- 

 brates during recovery from anaerobiosis are insufficient 

 to permit one to decide whether any special resynthesis 

 processes take place or whether delayed oxidations are 

 completed. 



