AEROBIC FERMENTATIONS 157 



ually differ greatly (in the eartliworm, for example, their 

 ratio is 1:5, ao3ording to Lesser, 1910), while they differ 

 much less if fermentative processes persist in the pres- 

 ence of oxygen (in Ascaris, von Brand, 1934a, found a 

 ratio of 1:1.32). 



The best evidence for aerobic fermentations is, of 

 course, the direst demonstration that non-oxidized or par- 

 tially oxidized substances have been formed under condi- 

 tions of good oxygenation. If one finds, for instance, 

 that an animal, like Moniezia, excretes exactly the same 

 amounts of non-oxidized substances in an atmosphere of 

 95 per cent oxygen and in the absence of oxygen and if 

 its oxygen consumption is identical in 21 per cent and 

 in 100 per cent oxygen (Alt and Tissher, 1931), then the 

 existence of true aerobic fermentations is certain. 



The distinction between partial transition to anaerobic 

 processes when oxygen is lacking, as outlined in the 

 preceding chapter, and aerobic fermentations is based 

 on the fact that, when more oxygen becomes available, the 

 cells which were forced to resort to anaerobic processes be- 

 cause of lack of oxygen, revert again to complete oxida- 

 tions, while those which carry on aerobic fermentations 

 continue to form non-oxidized or partially oxidized sub- 

 stances. 



It is usually found that the end products of incom- 

 plete oxidations are excreted. An accumulation in the 

 body will take place rarely, probably because it would 

 become injurious. The tw*© following cases might pos- 

 sibly represent exceptions to this rule. The proglottids 

 of tapeworms, w^hich are destined to live only a short 

 while, may suffer a certain accumulation of waste prod- 

 ucts (von Brand, 1933a). During the larval diapause of 

 some insects, in particular in the case of the Pyralidae 

 (Kozancikov, 1935) there is some evidence that end prod- 

 ucts of incomplete oxidations accumulate (though the 



