ACTION OF BACT. ABORTIVO-EQUINUS ON CARBOHYDRATES 471 



The inverted vial was used to determine gas production. A 

 portion of the medium, in the case of each carbohydrate, was 

 distributed in test tubes, and sterilized in the Arnold by steaming 

 twenty minutes for each of three successive days. Another por- 

 tion of the same carbohydrate medium was sterilized by filtra- 

 tion through a Berkfeld filter employing the apparatus shown in 

 figure 1. It will be noted from the cut that the test tubes are 



Fig. 1. Apparatus Showing Method of Sterilization of Media by Filtration 



1, Berkfeld filter case; 2, receiver of filtered media; 3, filling tube; 4, wash 

 bottle; 5, air cock; 6, water suction pump. 



filled directly through the tube 3. The glass tube attached to 

 the end prevents bacteria from dropping into the open test tube. 

 The inverted vials were filled by first coating the cotton plugs of 

 the tubes containing the medium with paraffin, allowing it to 

 harden, and then inverting which would permit the medium to 

 fill the vial. This unheated medium was incubated for forty- 

 eight hours and then allowed to stand forty-eight hours at room 

 temperature. The contaminated tubes were then removed. 



