MTKIENT MEDIA AM) METHODS OF CULTIVATION. 



119 



of neutralisation with carbonate of soda solution, the flask of broth 

 is placed m the steam steriliser for half an hour at 100 C. A 

 clear liquid results on nitration which is transferred to plugged 

 sterilised flasks or test-tubes, and sterilisation effected by exposing 

 them in the steam steriliser for half an hour at 100 0. for two 



FIG. 47. APPARATUS FOR STERILISATION BY STEAM UXDKK PKE>- 



or three successive days, or by-lusing the apparatus for sterilising 

 by steam under pressure. For some bacteria a more suitable 

 cultivating medium is obtained by the addition of glycerine or 

 grape-sugar. 



Liquid Blood Serum. The preparation of blood serum has 

 already been described. ' It may be required for cultivations before 

 the final treatment by which it is solidified, for example, in the 

 method of drop-cultivation, and may be used with the addition of 

 glycerine or grape-sugar. Hydrocele fluid, peritonitic and pleuritic 



