178 S^OVRCES! OF ENEROy TN At^AEROBlOfiJH 



than if the aiiiiiials arc starved under aerobic conditions. 

 All the available data are, however, at best only semi- 

 quantitative. They were gained in the study of the car- 

 bohydrate content with the help of specific stains. More 

 adequate methods of chemical analysis have not yet been 

 used. The increased interest in bacteria-free mass cul- 

 tures of free-living protozoa in recent years will, it is 

 hoped, lead to such investigations in the near future. 



Not even semi-quantitative experiments have so far 

 been carried out with non-parasitic flagellates and rhizo- 

 pods. It would be of great value to study along such 

 lines organisms like Pelomyxa or Difflugia, the resistance 

 of which in anaerobic conditions is well known. These 

 animals store considerable amounts of polysaccharides 

 as evidenced by the findings of Stole (1900), Ziilzer (1904) 

 and Leiner (1924). But no analogous accumulation of 

 glycogen has been reported for the Amoeba species that 

 have been used in experiments on anaerobiosis. Unpub- 

 lished observations by the present writer on various 

 Hartmanella species and amoebae of the Umax type failed 

 to show any significant amount of polysaccharide. 

 ■ Glycogen and paraglycogen are unquestionably im- 

 portant reserve substances for the anaerobic metabo- 

 lism of parasitic protozoa, although usually only the stor- 

 age of these substances and not their actual consump- 

 tion has been demonstrated. It has thus been shown that 

 the flagellates Giardia and various trichomonads accumu- 

 late considerable glycogen reserves (Deschiens, 1924; 

 Giovannola, 1934; Stewart, 1938; Stewart-Lyford, 1941) 

 and that glycogen or paraglycogen occurs in parasitic 

 ciliates like Balantidium, Opalina and Nyctotherus 

 (Biitschli, 1887; Barfurth, 1885; Jirovec, 1926; Kedrow- 

 sky, 1931; Armer, 1944). 



A remarkably intensive glycogen metabolism is found 

 in the ciliates parasitizing the stomach of ruminants and 

 it may also occur in the related species found in the 



