The series consists of chiefly of letters written by Osler that Cushing collecting during the preparation of his biography, The Life of Sir William Osler, between the years of 1920 and 1924. The letters in the series include both originals and transcriptions. The series also contains accompanying notes (both by Cushing and by Osler), clippings, articles, and other ephemera related to Osler.

Consists of books formerly belonging to the Library of the Medical College. These include:

• Kilgour, Frederick G. The Library of the Medical Institution of Yale College and its Catalogue of 1865. Yale University Press, 1960.
• Fenwick, George Edgeworth. Excision of the Knee-Joint. Dawson Brothers, Montreal, 1884.
• Renouf, E. M. Illustrations of the Medical Faculty, McGill University. McGill Faculty of Medicine, n.d.
• Shastid, Thomas Hall. The Description of an Opthalmoscope. Chicago: Cleveland Press, 1916.
• Casey Wood Collection. Letter inside from Thomas Hall Shastid, Feb 5, 1916.
• Holmes, A. F. Valedictory Addresses 1860-1861.
• Francis. W. W. Bibliotheca Osleriana. Oxford University Clarendon Press. Presented to the Cataloguing Department by W. W. Francis.
• Wood, Casey Albert. The Fundus Oculi of Birds Especially as Viewed by the Ophthalmoscope. Chicago: The Lakeside Press, 1917. Inscription to Maude Abbott “with compliments of the Author”
• Adams, Robert. Illustrations of the effects of Rheumatic Gout or Chronic Rheumatic Arthritis, on all the artiticulations; with descriptive and explanatory statements. MDCCCLVII
• Liebreich, Richard. Atlas D’Ophthalmoscope. 1863.
• Wagner, Daniel. Botanik oder Beschreiburg und Abbildung. Vienna (Wren), 1829.
• Benjamin, Martha. The McGill Medical Library 1829-1929. McGill University, 1960.
• Thesis for the Degree of Master of Library Science

Series D consists of photographs, postcards, slides, x-rays, and other visual material and artifacts such as copper printing plates. The visual material is located within other series, particularly the Correspondence Series A, but described individually here.

This series consists of notes and collected documents related to Dr. Segall's History of medicine research. This material includes records related to his various history research projects including his N.S. Korotkov book (1980), "Pioneers of Cardiology," material concerning the Osler Library of the History of Medicine, and correspondence with other medical historians.

This series consists primarily of various medical apparatuses, 3 voice recording machines, 4 electrocardiogram recording machines, magnetic recordings, audiograph recordings, and glass slides.

This series contains personal and family records of various kinds. Examples include correspondence, school and university study notes, official and unofficial documents, financial records, and photographs.

This series consists of Dr. Segall's medical research records, lecture notes, presentations, publications, and related material. While wide-ranging, the subject matter of these various kinds of materials often intersects. For example, his research records often influenced his publications and were reflected through his lectures. This interconnectivity may explain why such different forms of records were stored together. However, there are also many examples of files and boxes within the series where there are no obvious interconnections between different records.

This series consists of alphabetically ordered office files, mostly from the 1980s. The files contain material concerning various medical and history of medicine associations. There are also a small number of files on various colleagues and patients. These files do not include patient files with case histories.

This series consists of patient records which are not arranged as part of a larger set of patient files. The reason(s) why these records were separated from the patient records in series A through F, H, or L is/are not known.