The fonds largely document Dr. Segall's professional activities as a cardiologist. It contains correspondence, notes, experimental notebooks, lecture notes, articles, speeches, patients' records, electrocardiograms, reprints and material pertaining to the Louis Gross Memorial Lectures, 1922-1979. Also included are several electrocardiograph machines, dictation devices, and audio recordings (reel-to-reel tapes, dictation disks, and cassette tapes). In addition, the fonds contain records of Dr. Segall's personal and family correspondence, financial transactions, and various other official and unofficial documents.

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 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 contains miscellaneous medical practice files, medical practice financial records, medical practice correspondence, and decorations, memorabilia, and other objects from Dr. Segall's office. While various materials from this series may be found within a single box, there is not necessarily any recognizable connection between those materials.

This series is formed of publications and other materials concerning various medical and history of medicine associations and organizations, including correspondence between Dr. Segall and others about such associations and organizations.

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.

Sub-series consists of patients records started after 1973, and which were consulted between 1973 and Dr. Segall's retirement.

This series consists of the records of patients who died between 1926 and 1984. Like most other patient files of the fonds, almost all of these files contain heart sounds diagrams drawn by Dr. Segall, 6x12" clinical history forms, sections of electrocardiograms attached to dated cards, as well as 4x6" normal heart sounds record forms completed by Dr. Segall which are often accompanied by sections of electrocardiogram readings. Many files also contain correspondence between Dr. Segall and other doctors, medical institutions, and health insurance companies, and occasionally correspondence between Dr. Segall and the patient and/or the patient's family. In addition, some of the series' records are accompanied by a clipping of the patient's newspaper obituary.

Sub-series consists of patients records started prior to 1973, and which were consulted between 1973 and Dr. Segall's retirement.