1897] MICROSCOPICAL JOURNAL. 149 



FVeparation of Culture Media with Special Reference to 

 Sterilization. 



By IvAYMoni) C. Rkkd, Ph. B. 



[Assistant in the Department of Comparative Pathology <i'hI Bacteriology, 



New York State Veterinary College, Cornell University, Ithaca, N. V.] 



The amount of cnltiirc media used by the students in 

 a bacteriological laboratory is so great that its prepara- 

 tioti after the method given in the text books occupies 

 an undue propoition of the time allotted to this subject. 

 If it is pre{)ared by an assistant and furnished to the 

 students it not only takes miudi of his time, but it de- 

 prives the student of the opportunity of learning one of 

 the most important processes necessary for successful 

 work in bacteriology. Hence any change which will 

 shorten the time re(pured for its preparation will be of 

 value. When it is prepared by the usual method rec- 

 ommended in text books on Bacteriology at least three 

 days are necessary to complete the process of steriliza- 

 tion. The method of sterilizing;' by which the media is 

 heated to a somewhat higher tenjperature than 100° C. 

 by means of superheated steam is open to the objection 

 that the nutritive properties are impaired to a greater or 

 less extent for certain species of bacteria. 



In 1890 Moore* published a paper giving the method 

 employed in the Bureau of Animal Industry for making 

 nutritive agar and which s(^ems to be the one recommended, 

 with slight variations as to details, in the greater num- 

 ber of bacteriologies. The two most important changes 

 suggested were, (1) that wh(>n the agar was made from 

 meat infusion instead of meat extract, it siiould be pre- 

 pared from bouillon which could be made up in quanti- 

 ties and kept stored in flasks as stock ready for use. This 

 applies not only to the making of agar but also gelatin 



*The Preparation of Nutritive Agar. By V. A. Moore, M. D., Ameri- 

 can Microscopical .Tonrnul. May, l>^!)r). 



