INTRODUCTION 



At the request of the Society of American Bacteriologists, the Hterature was 

 surveyed for formulae of culture media reported useful for the growth of bacteria 

 and other microorganisms. The standard periodicals such as the various Cen- 

 tralblatts fiir Bakteriology, Zeitschrift ftir Hygiene, Annals of the Pasteur 

 Institute, Journal of Hygiene, Journal of Pathology and Bacteriology, and all 

 of the American bacteriological journals were perused from their inception to 

 the year 1926. A number of other periodicals, as well as text books, monographs 

 and many Experiment Station bulletins were included in the survey. 



Formulae of about seven thousand culture media were gleaned from the 

 literature. These were arranged and classified into approximately twenty five 

 hundred quite distinct media. A number and a distinctive name was assigned 

 to each medium which is described under the following headings: — Constituents, 

 Preparation, Sterilization, Use, Variants, so as to facilitate comparison of differ- 

 ent formulae. 



A dichotomous key, several indices and complete references to all articles 

 from which formulae were taken are also included in this compilation. In the 

 key, and all indices, the numbers refer to medium numbers and not pages. 



The Medium Name Index includes an alphabetical Ust of all media described 

 herein. 



In the Constituents Index an attempt was made to list every medium in 

 which a particular substance was employed. 



The Author Index is self explanatory. 



The Use Index is necessarily incomplete. It includes only those media for 

 which a specific use was indicated in the original article reviewed. 



The various media were subdivided into seven "groups" on the basis of their 

 physical states. Thus, all the liquid media are considered in a group by them- 

 selves and the solid media are further subdivided, on the nature of the solidifying 

 agent and physical properties of these agents, as, for example, whether initially 

 hquid, reversibly liquid and solid, or permanently solid. 



Each group, if sufficiently complicated to warrant further classification, is 

 then subdivided into ''sub-groups" on the basis of the presence or absence of 

 additional organic constituents. 



The sub-groups are further subdivided into sections on the basis of the nature 

 of the nitrogen, carbon, and inorganic constituents. 



For each section there is prepared a key, generally dichotomous, by means of 

 which each medium therein may be located. The various keys are distributed 

 throughout the book immediately preceding their respective media. 



The problem of a suitable means of identification of individual media was a 

 particularly difficult one. The scheme finally adopted was to assign a number in 



