66 PURE CULTURE OP BACTERIA 



Anaerobic organisms when grown in broth, milk and other 

 liquid media, very frequently give rise to the evolution of much 

 gas, which, in a completely sealed vessel, is likely to lead to 

 dangerous explosions. 



On this account it is best to arrange for their culture in liquid 

 media in yeast flasks, arranged as indicated in Ex. 140, where 

 a simple mercury valve allows of the escape of gas without 

 permitting the entrance of air. 



