THE PREPARATION OF CULTURE MEDIA 



41 



lised and inoculated with the anaerobic organism under 

 examination ; it is then placed in a larger tube contain- 

 ing broth which has been infected with bacillus subtilis, 

 or some other organism which rapidly 

 consumes oxygen. This outer tube is 

 then tightly closed with an india-rubber 

 stopper, which may be further coated 

 and sealed with paraffin. The oxygen 

 is rapidly removed from the entire closed 

 space by the vegetation of the bacillus 

 subtilis in the outer vessel, thus per- 

 mitting the growth and development of 

 the anaerobic organism in the inner 

 tube. 



Instead of using the culture of bacillus 

 subtilis in the outer tube, it is more con- 

 venient to employ a mixture of caustic 

 potash and pyrogallic acid, 1 which, as 

 is well known, rapidly absorbs oxygen. 

 The arrangement is shown in fig. 10. 



A useful summary of the various 

 methods which have been devised for 

 anaerobic culture is given by Novy in 

 the ' Centralblatt fiir Bakteriologie,' vol. 

 xiv., 1893, p. 581. 



FIG. 10. ANAERO- 

 BIC CULTURE. 



a, small test-tube con- 

 taining culture ; 6, 

 larger test - tube 

 containing pyro- 

 gallate of potash 

 solution ; c, india- 

 rubber stopper. 



1 The solution of caustic potash should consist of equal weights of 

 caustic potash and water, the pyrogallic acid is employed in nearly satu- 

 rated solution, and one volume of this is mixed with ten volumes of the 

 potash solution at the moment when required. 



