INFECTIONS OF THE DIGESTIVE TRACT 27 



It is conceivable that under such conditions as those 

 just mentioned, it becomes a matter of indifference to 

 the anaerobes how little oxygen is contained in the sur- 

 rounding air. On the other hand, it is well known that, 

 paradoxical as it seems, the strictest anaerobes known 

 are able to grow freely in apparently close contact with 

 a fairly abundant supply of oxygen, provided aerobic 

 bacteria are also present. Pasteur, to whom this note- 

 worthy symbiotic phenomenon was known, ascribed it 

 to the circumstance that the aerobes remove the oxygen 

 present in so thorough a way that the anaerobes are 

 unhindered in their growth. This doctrine, which 

 found wide acceptance, has lately been questioned by 

 Kedrowski * (and others), who attribute the ability of 

 anaerobes to grow symbiotically with aerobes to the 

 formation of a "ferment" by the latter, which renders 

 the anaerobes immune to the action of oxygen. It 

 cannot be said that this hypothesis has received sub- 

 stantial support, and we are compelled to return to the 

 teaching of Pasteur or to some modification of it. 2 There 

 is a limit to the amount of oxygen which the aerobes 



1 " Ueber die Bedingungen unter welchen anaerobe Bakterien 

 auch bei Gegenwort von Sauerstoff existiren konnen," Zeitschr. 

 f. Hyg., xx, p. 358, 1896. 



2 See Walter von Oettingen, "Anaerobic iind Symbiose," 

 Zeitschr. /. Hyg., xliii, p. 475, 1903. This writer contends that 

 the primary action in aerobic and anaerobic symbiosis is the split- 

 ting action of the anaerobes in sugar with their associated inability 

 to appropriate the oxygen contained in carbohydrates, that oxy- 

 gen being eagerly seized by the aerobes for their use. It is hard to 

 reconcile this view with the retarded growth of the anaerobes (as 

 compared with the aerobes) in some symbiotic experiments. In 

 this paper will be found the literature on the subject. 



