222 ANAEROBIC MI:TMU>IJ^M 



fact that most specimens, which have their intestinal 

 crura filled with food material, regurgitate their con- 

 tents when kept outside the host. One recovers there- 

 fore a mixture of true metabolic end products and of food 

 in various stages of digestion. Flury and Leeb (1926) 

 found ammonia, coagulated protein, albumoses, peptones 

 and amino acids, besides traces of hydrogen sulfide, haem- 

 oglobin, oxyhaemoglobin and methaemoglobin, in a sa- 

 line solution in which Fasciola and Dicrocoelium had been 

 kept for several hours. It seems evident that some of 

 these substances, especially the higher proteins and the 

 haemoglobins, were not true excreta, i.e., that they did 

 not originate in the cellular metabolism of the worms. 



In Hirudo medicinalis also Braconnier-Fayemendy 

 (1933) found ammonia as one of the chief end products. 

 The ammonia nitrogen represented 77.7 per cent of the 

 total eliminated non-protein nitrogen in anaerobic con- 

 ditions, as against 72 per cent in starving leeches kept 

 under aerobic conditions. The corresponding figures 

 for amino acid nitrogen were 1.14 and 1.27 per cent, and 

 those for creatinine nitrogen 1.22 and 2.14 respectively. 



The anaerobic protein metabolism of the earthworm 

 must be different from that of leeches. Lesser (1909a) 

 reported that only very little, if any, ammonia resulted 

 from protein degradation in an atmosphere deficient 

 in oxygen. 



The curious observations of Harnisch (1939) on the 

 larvae of Chironomus thummi, which seem to indicate 

 that, during anaerobiosis, there occurs an increase in ni- 

 trogen which can be determined by Kjeldahl's method, 

 have already been mention^'d in the preceding chapter. 

 A definitive evaluation oi 'he significance of these data 

 will only be possible when more experiments have been 

 performed. In a recent paper Harnisch (1943) states 

 that the larvae of Chironomus hafhophiliis excrete con- 

 siderable amounts of ammonia when kept in nitrogen. 



