METHOD OF STRAUSS AND WURZ 



101 



gelatine (liquefaction). The germs may then be isolated 

 by further transference to culture plates, and submitted to 

 microscopic examination. 



Glass tube 



J lubber cork 



Aspirator 



FIG. 31. HESSK'S APPARATUS FOR EXAMINING AIR. 



Method of Strauss and Wiirz. Air is drawn into a glass 

 vessel full of liquid gelatine by means of a tube affixed to 



Aperture for the admission of air 



Vessel filled with gelatine 



Lateral tubuluie 



FIG. 32. Aiu-TKSTiNG APPARATUS OF S'IRAT ss AND WURZ. 



the side and connected with an aspirator (fig. 32). A large 

 volume of air, 100 to 200 litres, is thus tested, and when 

 the aspiration is concluded the gelatine is poured out on 



