88 BACTERIOLOGICAL ANALYSIS LESSONS 



15 grammes of sheet gelatine, and heat slowly in a beaker, 

 placed in a water bath, till all the gelatine is dissolved. 



(2) Neutralise in the usual manner, and again heat for 

 half an hour to one hour. 



(3) If necessary, clear with the white of an egg. 



(4) Then filter through a hot- water funnel into a sterilised 

 flask. 



(5) Fill test-tubes in the usual manner, and sterilise them 

 on two successive days. 



Grape-sugar gelatine is employed for anaerobic 

 cultivation, and 25 per cent gelatine is especially 

 useful in the diagnosis between the bacillus of 

 typhoid fever and the Bacterium coli commune. 



VII. CARBOLIC ACID GELATINE. 



(1) To every 100 cc. of liquid 10 per cent gelatine add 

 4 cc. of a 5 per cent solution of pure carbolic acid. 



(2) Fill test-tubes in the usual manner, and sterilise them 

 on two successive days. 



This gelatine is most useful for the separation of 

 typhoid bacilli or of the Bacterium coli commune. 



VIII. PEPTONE SOLUTION. 



(1) To 10 grammes of pure peptone and 5 grammes of 

 sodium chloride add 1000 cc. of distilled water. 



(2) Boil for an hour, neutralise carefully in the usual 

 manner, and boil for another half-hour. 



(3) Filter into sterilised flasks, and sterilise in the auto- 



