VACUUM INCUBATORS 105 



vacuum bell jar has already been described. Tretrdp's (fig. 97), or Baginski's- 

 apparatus, or Adnet's vacuum incubator are also available. The last is a 



FIG. 97. Tretrop's apparatus, in which to grow anaerobic cultures. 



stout-walled incubator which can be hermetically closed by means of a door 

 with an india-rubber washer and is provided with a Roux's regulator and a 



gas burner. 



