CHAPTER V 



RECOVERY FROM ANAEROBIOSIS 



All invertebrates, with the exception of the few which 

 are adapted to permanent life in the complete absence 

 of oxygen, become paralyzed after they have been deprived 

 of oxygen for a certain time. Most terrestrial insects, 

 for example, lose their motility in a few minutes, often in 

 a few seconds. Other invertebrates that show better 

 adaptations to anaerobic life, like many worms, may re- 

 main active for several days, but they too will finally be- 

 come quiescent. In general, paralysis is due to the ac- 

 cumulation of non-oxidized substances within the body: 

 these substances usually exert some toxic action. But if 

 the anoxic period is not too long the animals recover 

 upon readmission of oxygen. This recovery can be 

 studied from various angles; w^e shall discuss here (1) 

 the time required for recovery; (2) the post-anaerobic 

 gas metabolism; and (3) the chemical nature of the re- 

 covery processes. 



1. TIME FOR RECOVERY 



The most generally used sign of recovery is the re- 

 sumption of some form of movement : either — in the case 

 of protozoa — amoeboid, flagellar or ciliary movement, 

 or merely the functioning of contractile vacuoles or of 

 other organelles, or — in the case of metazoa — actual lo- 

 comotion or only the moving of some appendage. Re- 

 ports of recovery are numerous in the literature : see in 

 particular, Emery (1869), Plateau (1872), Bert (1878), 

 Devaux (1891), Fielde (1904, 1904a), Collip (1920), Lee 

 (1924), Wrede and Kramer (1926), Haldane (1927), 

 Pantin (1930), Bruneteau (1931), Kitching (1939, 1939b), 

 Kalmus (1935, 1942). 



The time required for recovery, as measured by the re- 

 sumption of locomotion,' depends to a large extent upon 



