The Sir William Osler Collection, distinct from the Bibliotheca, is an extensive archival holding of Osler's correspondence (including eighteen hundred original letters), daybooks, accounts, engagement books, legal documents, book invoices, membership certificates, notebooks, lectures, addresses, newspaper clippings, photographs, books with manuscript additions, and miscellaneous loose items formerly inserted into individual books in his library. The collection also contains various family papers, including correspondence of Lady Grace Revere Osler and Edward Revere Osler.

Fonds contains diplomas, certificates from medical associations, and photographs relating to Robert Palmer Howard and Alan Campbell Palmer Howard.

The collection contains private records and papers relating to the medical and teaching career of Maude Abbott. It consists in large part of correspondence, 1894-1920, including family correspondence with, among others, her sister Alice Abbott, 1904-1919, and her brother Rev. Harry M. Babin, 1916-1920. Also included are manuscripts and drafts of articles and addresses; case reports; post-mortem records; glass slides and drawings; exhibit panels largely pertaining to her research on congenital heart disease; programmes of medical meetings, 1902-1937; reprints and papers relating to the history of medicine in Montreal and Quebec, as well as to the history of McGill, 1829-1936. In addition, there are photographs, some poems, an autobiographical sketch and a printed copy of her Classified and Annotated Bibliography of Sir William Osler's Publications, 1939, with corrections and annotations by W. W. Francis. Fonds also includes a draft of Abbott's letter to the Dean of Faculty of Medicine, McGill University, regarding admission (1889).

Collection includes a scrapbook and a file of memorabilia of Dr. Anderson and his family, 1894-1952. It contains letters, menus, programmes, certificates, a manuscript of a poem, a contract to purchase, ferrotypes, and many newspaper clippings.

This collection is divided into material either by, or about, Wilder Graves Penfield. The material was collected by Lewis in order to write his biography. The fonds also includes materials associated with Mr. Lewis' writing of the biography.

The Penfield material is organized by family member, with the largest portion belonging to Wilder Penfield and his wife Helen Penfield. This material is largely personal in nature. It consists of originals and photocopies of diaries, as well as personal correspondence between Penfield and his wife, family photographs, and ephemera from a variety of social and professional events. There is also a small selection of personal correspondence between family members.

Lewis created drafts, revisions, letters concerning the development of the screenplay, and research material. Correspondence between Lewis and the family is contained in the material covering personal family matters.

The collection contains correspondence, curriculum vitae, a poem written by his wife, Elizabeth Turnor, a record of medical examinations for the Coroner's Court of Montreal, 1894 and lectures notes. The greater part of the notes consists of embryology notes made at the Anatomisches Institut, Munich, around 1900.

The collection consists of seven volumes of Elliott's personal diaries, which were bound together, at his own expense, after their completion. These diaries cover the five-year period that Elliott spent serving overseas, primarily in England. The contents of the journals include handwritten entries, sketches and watercolours that were either executed in the pages of the diary or pasted in, and photographs, newspaper clippings, letters, playbills, menus and other paraphernalia that were also pasted into the diary. These serve to document both the development of the war and Elliott's personal experiences. The diaries are generally in chronological order although there are places, particularly in the last three volumes, where the diaries have been bound out of sequence.

The fonds also contains several folio sheets of photographs and clippings regarding Elliott's career.