ANACROBIC CULTURES 



243 



(or the delivery tube of a Kipp's Fig. 132 or other 

 hydrogen apparatus, Fig. 133), interposing a short 

 piece of glass tubing; and in like manner connect a 

 long piece of rubber tubing which should be led into 

 a basin of water, to the opposite side tube. 



6. Open both metal clips and pass hydrogen through 

 the vessel until the atmospheric air is replaced by 

 hydrogen. This is determined by collecting some of 

 the gas which bubbles through the water in the basin 

 in a test-tube and testing it by means of a lighted taper. 



7. Close the metal clip on the tube through which 

 the gas is entering ; close the clip on the exit tube. 



8. Disconnect the gas apparatus. 



9. Incubate. 



Method X (Botkin's Method) .- 



Apparatus Required. 



Large glass dish 20 cm. diameter and 8 cm. deep. Flat leaden 

 cross slightly shorter than the internal diameter of the glass dish. 

 Bell glass about 15 cm. diameter and 20 to 25 cm. high. 

 Metal frame for plate cultivations. 

 Or, glass battery jar for tube cultivations. 

 Cylinder of compressed hydrogen. 

 Rubber tubing. 



Two pieces of U-shaped glass tubing (each arm 8 cm. in length). 

 Half a litre of glycerine (or metallic mercury). 



METHOD. 



1 . Place the leaden cross inside the glass dish, resting 

 on the bottom. 



2. Prepare the cultivations in the usual way. 



3. Place the tube cultivations in a glass battery jar 

 (or the plate cultivations on a metal frame) , resting on 

 the centre of the leaden cross. 



4. Cover the cultivations with the bell jar. 



5. Adjust the U-shaped pieces of glass tubing in a 

 vertical position on opposite sides of the bell jar, one 

 arm of each inside the jar, the other outside. These 

 tubes are best held in position by embedding the U- 



