26 INFECTIONS OF THE DIGESTIVE TRACT 



concerned are subsisting without access to any oxygen 

 whatsoever, and the term "strict anaerobe" tends to 

 give fixity to such a conception. Such an idea, however, 

 would be far from expressing the actual truth, since there 

 is no known exception to the rule that living microorgan- 

 isms cannot maintain themselves without producing 

 carbon dioxide, a process which involves the oxidation 

 of organic materials within the cell. But the quantity 

 of oxygen required to maintain life may be extremely 

 small, and it is in this sense only which is expressed in 

 the term "micro-aerophile," suggested by Beijerinck 1 

 that we are justified in speaking of anaerobic micro- 

 organisms. It has been calculated by Matzushita 2 

 that anaerobes may live although the surrounding air 

 contains not more than 0.0031 per cent, of oxygen. 

 This fact is liable to mislead us if we accept it as meaning 

 more than that the presence of very little oxygen in 

 the air is consistent with the maintenance of some 

 forms of microorganic life. For, on the one hand, it 

 seems clear that microorganisms may obtain their small 

 portion of essential oxygen not from the air, but from 

 a medium containing a decomposable substance which, 

 like glucose, contains oxygen which becomes available 

 for the support of life. In other conditions the body of 

 the microorganism may contain material which is capable 

 of yielding oxygen for a time, in minute amounts. 



1 Arch. Norland, ii, 1899. 



2 "Zur Physiologic der Sporenbildung der Bacillen, nebst 

 Bemerkungen zum Wachstum einiger Anaeroben," Archiv /. Hyg., 

 xliii, p. 327, 1902. 



