CULTURES OF ANAEROBES IN LIQUID MEDIA 67 



in the other ought to be partially drawn out in a flame to 

 facilitate subsequent complete sealing. The ends of the tubes 

 through which the gas is to pass are previously protected by 

 pieces of cotton wool tied on them. It is well previously to 

 place in the tube, through which the hydrogen is to be delivered, 

 a little plug of cotton wool. The flask being thus prepared, it 

 is sterilised by methods B (2) or B (3). On cooling it is ready 

 for inoculation. In the case of the flask with the lateral nozzle, 

 the cotton-wool covering having been momentarily removed, a 

 wire charged with the organism is passed down to the bouillon. 

 In the other kind of flask the stopper must be removed for an 

 instant to admit the wire. The flask is then connected with 



FIG. 24. 



a. Flask for anaerobes in liquid media. Lateral nozzle and stopper fitted 

 for hydrogen supply, b. A stopper arranged for a flask without lateral nozzle. 



the hydrogen apparatus by means of a short piece of sterile 

 indiarubber tubing, and hydrogen is passed through for half an 

 hour. In the case of flask (1), the lateral nozzle is plugged 

 with melted paraffin and covered with alternate layers of cotton 

 wool and paraffin, the whole being tightly bound on with string. 

 The entrance tube is now completely drawn off in the flame 

 before being disconnected from the hydrogen apparatus. In 

 the case of flask (2), first the exit tube and then the entrance 

 tube are sealed off in the flame before the flask is disconnected 

 from the hydrogen apparatus. It is well in the case of both 

 flasks to run some melted paraffin all over the rubber stopper. 

 Sometimes much gas is evolved by anaerobes, and in dealing 

 with an organism where this will occur, provision must be made 

 for its escape. This is conveniently done by leading down the 



