266 



MICROBES, FERMENTS, AND MOULDS. 



meat. The flasks are all modifications of the form 

 indicated in Fig. 76. These flasks are heated in an 

 iron gas stove (Fig. 104), of which the double case is 

 heated by gasburners, and it contains a basket of iron 

 wire as the receptacle of the flasks, tubes, etc., which 



Fig. 106. — Stand, bearing culture tubes. 



are to be sterilized. The temperature, regulated by a 

 thermome.ter, must rise to from ] 50° to 250°. 



The nutritive liquid is boiled in a porcelain cru- 

 cible in the open air, and is introduced by breaking 

 off' the tapered end of the flask ; it is then instantly 

 plunged into the broth, and drawn by an aspiration 

 through the opposite tube, after which the tapered 

 end is resealed at the lamp. 



