72 



BACTERIOLOGY. 



good results are to be obtained, i. e., if a translucent, 

 solid medium is to result. If the old, small form of 

 apparatus is employed (Fig. 7), then the solidification 

 can be accomplished in a shorter time than if the larger 

 forms, which are now frequently employed, are used. 

 No definite rule for the time that will be required can 

 be laid down, for this is not constant. If the small 

 solidifying apparatus is used, very good results may be 

 obtained in about two hours at 78 C. It frequently 

 requires a longer time at a higher temperature than 

 has been mentioned This is especially the case with 

 LofHer's serum mixture. 



FIG. 7. 



The best results are obtained when a low temperature 

 is employed for a long time. Under any circumstances 

 ^the tubes must be observed from time to time through 

 the glass door or cover with which the solidifying oven 

 is provided, and each time the oven should be slightly 



