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.

Typed copies of the official and private correspondence, 1814-1821, held in the McCord Museum in the William MacKay Papers. They consist mainly of military records such as commissions, 1813-1814, correspondence between members of the British Indian Department, including Lt. Col. Robert McDouall and his description of the siege of Prairie du Chien, regarding the Omaeqnomenew (Menominee), Hocak (Winnebago), and Meskwaki (Fox) warriors who fought alongside British forces, as well as to the Potawatomi leader Main Poc (referred to as Marpock), 1814-1815 and copies of correspondence of Capt. Thomas Anderson with Lt Col. Robert McDouall on military actions, supplies and Indian relations, 1814-1815. It also includes two transcribed copies of a newspaper article about Alexander MacKay and the partnership agreement admitting William MacKay and David Mackenzie into the North West Company in 1796.

This collection consists of contemporary copies of letters written by T. Blackwood from Michilimackinac to James and Andrew McGill & Co., to Ch. Chaboillez, and to T. and J. McGregor.

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.

There is business correspondence, 1792-1800, with letters from among others Alexander Mackenzie, Joseph Frobisher, Alexander Henry, Simon Fraser and Roderick Mackenzie. There are also minutes and resolutions of the Executors of McTavish in a bound volume; and a contemporary copy of the minutes of the executors of his will, 1805.

There are three letters from Lord Selkirk, one from Lord Dalhousie, and eight from Lady Selkirk. The early letters concern the Red River Settlement and the North West Company. The letter from Lord Dalhousie, 1824, concerns legal matters, and the two late letters, 1828 and 1833, from Lady Selkirk are personal in nature.

Letters and diaries, including typescript transcriptions with photographs, newspaper clippings and ephemera.

Collection of correspondence between the years 1818 and 1828, predominantly on the matters of The Society of Antiquaries of London, addressed to Daniel Lysons, a British antiquarian and topographer. Comprises 25 letters mounted on paper. The first letter of September 5, 1818, is addressed to Samuel Lysons (1763-1818).

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).

Consists of an English translation of a letter to the Marquis de la Jonquière written by Antoine-Louis Rouillé, comte de Jouy, secretary of state for the French Navy, at Versailles, dated 28 February 1750. The letter discusses an immediate release of prisoners of war taken during conflicts between the French and British colonies. It also includes a mention of Indigenous allies of England and France, and Indigenous people captured during the conflicts: "the Indian Prisoners among the two Nations be likewise released, but after all the French and English Prisoners are released" The letter also includes the name of examiner Josiah Willard, secretary of the province of Massachusetts-Bay.