104 BACTERIOLOGICAL ANALYSIS LESSON v 



(4) Pour plates in the usual manner, and when the agar- 

 agar is firmly set, place them in the warm incubator, lid 

 downwards, so that the condensation water does not collect 

 on the surface of the agar-agar. 



(5) Examine the plates next morning microscopically, 

 and make subcultures in gelatine (stab cultures), on agar- 

 agar (streak cultures), and in peptone. 



Keep the gelatine tubes at 22 C., the agar-agar and 

 peptone tubes at 38 '5 C. 



(6) After twenty -four hours examine microscopically, 

 and test the peptone tubes for " Cholera Ked." 



This method often yields quick results. 

 IV. Gelatine plates. 



(1) Liquefy three gelatine tubes and inoculate the first 

 with *25 to *5 cc. of the suspected water. 



(2) Proceed exactly as in the case of the agar-agar 

 tubes described above. 



(3) Prepare three plates and keep them at 22 C. 



(4) Examine these from day to day microscopically, and 

 also make subcultures in the manner stated above. 



Unmistakable colonies will be found after thirty-six 

 to forty-eight hours. 



