The records in this series consist of admission and discharge books for overseas medical units in which Canadian soldiers were treated during the First World War. Many of those medical units were Canadian ones, but the series includes British and Australian ones as well. Known as Admission and Discharge Books, this series contains two kinds of books: the first kind identify - in ledger format - the soldier by name, regimental number, providing the name of the unit, the age, number of months in service, religion and indicate the nature of the illness/wound and the dates of admission and discharge. The second kind of books includes the same information with additional details on treatment or operation performed. Details on operations performed usually provide name of the patient, date of the treatment precision on the illness or wound, the name of the doctor who performed the treatment, and sometimes status of the recovery. The books cover the period 1914-1920.
The medical units were located in England and the Western Front and include field ambulances, casualty clearing stations, ambulance trains, as well as general, stationary, convalescent, special, voluntary aid detachment (VAD), ship (and ambulance ship), war and military hospitals.
In a note sent by Surgeon-General M. W. Russel (Book 1598), British hospital authorities are reminded of the procedures regarding records of Canadian patients. A list was to be made of all officers and other ranks admitted during the week and of those discharged during that time. Also, hospitals were to list all Canadian patients under their care. Those lists were to be sent each Friday to the Director of Medical Services in London.
Medical units kept distinct books in which were noted all admission and discharge for Canadian patients. In most cases, officers were recorded in separate books, while NCO (non-commissioned officers) and O.R. (other ranks) are usually found in the same books. In a few cases, all officers, NCO and O.R. can be found in the same book. Some medical units kept separate books for Canadians transferred from the front or coming from camps in England: in these cases, the mention "UK Canadian Troops", UK Canadians" or "UK Colonials" will appear on the book. Finally, some books only list the nursing sisters.