PRACTICAL OBSERVATIONS ON THE TITRATION 

 AND ADJUSTMENT OF CULTURE MEDIA 



BERTHA VAN HOUTEN ANTHONY and CLARENCE V. EKROTH 



Bureau of Laboratories, Department of Health, City of New York 



Any one who studies the methods given in the various text- 

 books for the titration and adjustment of culture media, must 

 be struck by the lack of uniformity of opinion. Not only is the 

 beginner in media preparation bewildered but even the more 

 experienced worker may be led into error. The difficulty arises 

 from the fact that the complex nature of the materials dealt 

 with is by no means fully understood, even in the case of the 

 most fundamental culture media. In addition to this the 

 changes that occur under even slightly different conditions and 

 treatment are most confusing. As a result each laboratory 

 is compelled to adopt the methods best adapted to its work and 

 requirements, and each laboratory makes changes m these 

 methods as need arises. 



The many requests constantly made for information regard- 

 ing the methods employed in our laboratories for the titration 

 and adjustment of both general and certain special culture media 

 seem to indicate the need for a detailed account of such pro- 



cedures. 



In this paper we have tried to incorporate the practical in- 

 formation gained after a number of years of experience. In 

 addition, we have described experiments carried on with a 

 view of clearing up, in a systematic manner, certam pomts upon 

 which Httle, if any, information is available. 



The Standard Method' of titrating media for water and milk 

 analyses was devised in an attempt to secure uniform prepara- 

 tions of media at all times so that comparable results might 

 be obtained. 



1 Committee on Standard Methods, 1905, 1913). 



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