SOURCES OF EXERGY IN AXAEROBTOSIS 177 



weight while, according to Schulte (1917) it is only 0.9 

 per cent. It seems i^robable, however, that both these 

 authors overestimate the sugar content of the ascarids; 

 their relatively high figures seem due to a partial hydro- 

 lysis of glycogen during the analyses. It should be noted 

 in this connection that Foster (1865) and von Brand 

 (1934a) found only traces of reducing sugars in these 

 helminths. 



Recent investigations have shown that sugar occurs to 

 the extent of 1.26 per cent in the larvae of Tenebrio moli- 

 tor and that it disappears at the rate of 50 mg. per 100 g. 

 per hour if the animals are kept in pure nitrogen (Gil- 

 mour, 1941). 



Many more similar cases will probably come to light 

 if more attention is paid to the occurrence of simple su- 

 gars in metazoa than has been done hitherto. 



B. Higher carbohi/d rates. Glycogen, its close relative 

 paraglycogen, and starch, are the polysaccharides most 

 commonly utilized during periods of deprivation of oxy- 

 gen and the most studied. Much less is known concern- 

 ing cellulose, dextrin and inulin, and nothing about para- 

 mylon and galactogen. 



(a) GLYCOGEN AND PARAGLYCOGEN. These two polysac- 

 charides diifer only in minor characters and can there- 

 fore be treated here together. Glycogen is stored in all 

 invertebrate phyla, paraglycogen onty in some protozoan 

 groups (gregarines and coccidia and probably some cil- 

 iates). The importance of these carbohydrates for en- 

 ergy production in anaerobic metabolism will be re- 

 viewed here briefly for the major phyla. 



Protozoa. It has repeatedly been reported that in 

 free-living ciliates, like Paramaeciwni, Stent or and others, 

 the polysaccharides stored in the body disappear under 

 anaerobic conditions (Piitter, 1905; Galadziev and Malm, 

 1929; Zhinkin, 1930; Liebmann, 1936; Barbarine, 1938). 

 The rate of consumption is then evidently much higher 



