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CHEMICAL CRITERIA OF ANAEROBIOSIS WITH 



SPECIAL REFERENCE TO METHYLENE 



BLUEi 



IVAN C. HALL 



From the Department of Hygiene and Bacteriology, University of Chicago 



Received for publication June 4, 1920 



The literature of anaerobic technology contains frequent 

 references to various criteria of anaerobiosis aside from growth 

 of organisms. To be sure, the successful cultivation of a known 

 anaerobic micro-organism under given conditions, in contrast 

 with the failure of growth of the same organism on the sm"face 

 of solid media of similar composition in free contact with air, 

 constitutes a satisfactory biological criterion of anaerobiosis for 

 the particular organism used in the test and under the special 

 conditions thereof. But there are circumstances in which it is 

 deshable to correlate other means of determining oxygen tension 

 reduction. An obviously useful physical means is the vacuum 

 manometer, but most helpful of all are chemical criteria, which 

 are usually based upon coloration changes. 



One of the earliest indicators used, and a notable exception 

 to the rule of indicators with coloration changes, was phosphorus, 

 whose failure to ignite was employed by Gratama, a student of 

 Gunning's (1877). 



A mixtm-e of alkah with pyrogalUc acid, as used in reducing 

 oxygen tension for the cultivation of anaerobic organisms, is 

 also frequently mentioned as affording a criterion of successful 

 anaerobiosis since in the absence of oxygen the solution remains 

 nearly or quite colorless. But it is scarcely possible for this 



.^__ 1 This essay is based upon an investigation completed during the writer's 



ex; tenure of the Logan Fellowship at the University of Chicago and is one of a 

 ^ series awarded the Howard Taylor Ricketts Memorial Prize for 1920. 



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~,. JOUHN.U, OF BACTERIOLOGY, YOL. VI, NO. 1 



