RECOVERY FROM AXAEROBIOSIS 243 



of the oxygen in the medium. Harnisch is of the opinion 

 that the experimental evidence does not favor the first 

 hypothesis, and he brings forward the following argu- 

 ments in favor of the second. (These arguments are de- 

 rived largely from observations on the respiration of par- 

 asitic worms.) It is a well-established fact that the oxy- 

 gen consumption of parasitic nematodes, trematodes and 

 cestodes is dependent on the oxygen tension (cf. Har- 

 nisch, 1932a, 1933a, 1937a; Kriiger, 1936; Laser, 1944). 

 Contrary to what one finds in actinians this dependency 

 is not materially changed if minced material is used in- 

 stead of intact animals and consequently the distance 

 through which oxygen has to diffuse cannot be the lim- 

 iting factor of its availability. Harnisch, therefore, as- 

 sumes that the greatest part, if not all, of the oxygen 

 consumed by parasitic worms corresponds only to the 

 post-anaerobic phase of the respiration (secondary aero- 

 biosis) of free-living animals. Parasitic worms would 

 thus show, at most, only traces of primary aerobic 

 processes. 



According to Harnisch (1937a, 1937b), an essential 

 distinction between primary and secondary aerobiosis is 

 that the enzymatic complex governing the primary proc- 

 esses is located within the cells, while that responsible 

 for the secondary processes lies outside the cells, in the 

 body fluid. Only the second of these complexes can 

 therefore be removed by washing (when minced material 

 is used). With this method it was found that in free- 

 living organisms, like Chironomus larvae, only the post- 

 anaerobic excess oxygen consumption disappears while in 

 parasitic worms almost the entire oxygen consumption 

 is eliminated. 



Harnisch 's evidence for a fundamental difference be- 

 tw^een primary and secondary aerobiosis seems good, on 

 the whole. Yon Buddenbrock (1939), however, raised 

 against this view the objection that the dependency of 



