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19th Century Schedule

• Not part of the main NLM Classification

• Accessible via a link from the NLM Classification homepage:
  https://classification.nlm.nih.gov/19century_schedule

• Simplified subject classification developed in 1956 that is derived from the letters that represent the preclinical and clinical subjects covered by the NLM Classification used for 19th century (1801-1913) materials. Used for monographs and serials (Exception: bibliographies follow the classification for modern bibliographies (Cf. Module 7—Bibliographies and Related Materials)

• Mostly limited to combinations of letters
  • QS, QSA, QSB, QT, etc.
  • Exceptions:
    • W1-6, W 26, W 600, WX 2, and form number 22 appearing throughout the schedule

• In addition, the entire WZ schedule is used for non-clinical19th century works

• When the subject falls outside of the scope of the schedules of the NLM Classification, only the letters of the LC schedule representing the subject are used
  • Examples:
    • BF for Psychology
    • SF for Veterinary Medicine

• Also used for facsimiles and reprints of works published between 1801-1913

• Classify here translations of works originally published from 1801-1913 only if the translation itself is published from 1801-1913