RECOVERY EROM AXAER0BWSI8 247 



corresponding to the post-anaerobic metabolism of free- 

 living organisms. It has, however, already been men- 

 tioned that other investigators could not obtain con- 

 firmation of Harnisch's findings; von Brand (1934a) 

 and Kriiger (1936) have shown that Ascaris forms more 

 carbon dioxide in aerobic than in anaerobic conditions. 

 The same authors (von Brand, I.e.; Kriiger, 1937) have 

 proven that the respiratory quotient of the aerobic proc- 

 esses of this worm lies between 0.9 and 1.0. They were 

 able to separate the carbon dioxide correlated with the 

 oxygen consumption from that coming from aerobic fer- 

 mentation, by taking into consideration the acid produc- 

 tion and correlating a certain amount of carbon dioxide 

 with the latter. Von Brand (1942), finally, found defi- 

 nite indications that the respiratory quotient of the post- 

 anaerobic i3rocesses of Eustrongylides is very similar 

 to that of the normal aerobic metabolism (1.06). He ob- 

 served that the quotient returned to normal as soon as 

 the carbon dioxide retention ceased. Since, however, as 

 mentioned above, the excess oxygen consumption of this 

 worm lasts longer than the carbon dioxide retention,, it 

 follows that the respiratory quotient of the oxidations 

 connected with the excess oxygen consumption must have 

 been near unity. Otherwise an abnormal quotient should 

 have been observed not only during the initial stages of 

 the excess oxygen consumption but throughout its whole 

 course. 



3. THE CHEMICAL NATURE OF THE RECOVERY PROCESSES 



It seems well established that, during the recovery of 

 frog muscle from anaerobiosis, one fourth of the ac- 

 cumulated lactic acid is oxidized to carbon dioxide and 

 water, and that the energy liberated thereby is used to 

 resynthesize the remaining three fourths to glycogen 

 {cf. Meyerhof, 1920). That a similar phenomenon occurs 

 also in invertebrates appears probable, though there 

 seem to be more possibilities than in vertebrates. In the 



