CULTURES OF ANAEROBES IN LIQUID MEDIA 69 



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

 with melted paraffin and covered with alterriate 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 



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. 



exit tube, and letting the end just dip into a trough of mercury 

 (Fig. 25), or into mercury in a little bottle tied on to the end 

 of the exit tube. The pressure of gas within causes an escape 

 at the mercury contact, which at the same time acts as an 

 efficient valve. The method of culture in fluid media is used to 

 obtain the soluble products of such anaerobes as the tetanus 

 bacillus. 



The Method of Tarozzi. This observer has found that if 

 small pieces of fresh sterile organs are added to ordinary bouillon, 

 growth of anaerobes takes place under ordinary atmospheric con- 

 ditions. For this purpose, portions of liver, spleen, or kidney 

 are most suitable. If after the piece of tissue has been added 

 the medium is boiled for a few minutes it loses its property of 

 growing anaerobes, but the temperature may be raised for a short 



