Three-way division combined with conversion to Medical Subject Headings(MeSH) in a medium-sized medical library.

Conversion to MeSH and other reasons are enumerated for the division of an undivided dictionary card catalog into a three-way divided catalog, consisting of Proper Names, Titles, and Topical Subjects sections. Methodology of division is described. Conversion from Library of Congress Subject Headings to Medical Subject Headings (MeSH) as an authority list stimulated such concurrent changes as (1) the introduction of a guide card system that eliminates typing of subject headings on catalog cards and (2) the adoption of a filing system that employs reverse chronological order for all types of sequential material in the Proper Names and Titles sections and for all material in the Topical Subjects section. The ancillary decisions, procedures, and methods necessitated by these major conversions are also described.