XV 

 THE PHYSIOLOGICAL EFFECTS OF LACK OF OXYGEN 



I. INTRODUCTION 



MORE than a century ago Spallanzani published his ob- 

 servations on the effect of stagnant air upon animals and 

 plants. Spallanzani introduced organisms into hermetically 

 sealed vessels of various sizes (which were, however, rilled 

 with air), and found that the smaller the vessel, the earlier 

 did all life cease to exist in it. He also observed that differ- 

 ent organisms show an unequal resistance to lack of air. 

 As the most remarkable case he cites Anguillula aceti: 

 "They live and multiply prodigiously where the volume of 

 air does not exceed three inches; and die in several days 

 only, when confined in a tube where the vacuum is less than 

 an inch." 



The further experiments on the same subject have fully 

 confirmed the observations of Spallanzani. Bunge, in his 

 well-known treatise on the respiration of mud-dwelling 

 organisms, concludes that apparently "all transitional 

 stages exist in the animal kingdom from the anaerobic 

 unicellular organisms up to the most highly organized 

 animals with a most energetic demand for oxygen. 1 ' 3 



A series of brilliant observations have served to elucidate 

 the chemical side of these phenomena. It is an established 

 fact that carbon dioxide can be produced in an organism 

 without the presence of oxygen. Hermann has shown that 

 the excised muscle of the frog is able 'to do work and to 



1 Pfiugers Archiv, Vol. LXII (1895), p. 249. 



2 SPALLANZANI, Tracts of the Natural History of Animals and Vegetables. 



3 Zeitschrift fur physiologische Chemie, Vol. XII 



370 



