306 



PHYSIOLOGY OF BACTERIA 



concentration. This might be accounted for by assum- 

 ing either an adsorption of oxygen by the bacterial 

 surface, or by a dissociation of the oxygen molecule into 

 atoms, O2 = 20, as in the slow oxidation of phosphorus. 



The data of Paul and his associates on the influence of 

 oxygen on dry bacteria have been confirmed and com- 

 pleted by Rogers (1914) who also controlled the moisture 

 content of dried streptococci. It seemed that the 

 less moisture was contained in the cells, the longer 

 they lived. Rogers dried his bacteria by placing the 

 culture in an evacuated desiccator over sulfuric acid 

 at freezing temperature. 



After being dried, the streptococci were tested for 

 viability in various gases. Only one count was given 



