Fonds documents Thomson's research, his consultations with government, and his involvement in learned societies and university associations. As well, a significant percentage of the material is of a nonprofessional and private nature, focussing on Thomson as a public speaker.

Papers devoted to research consist of 18 cm of background notes, summaries and extracts on nutrition, protein and carbohydrate metabolism, and vitamins. Approximately .6 m of card indexes contain summaries of Thomson's professional reading in the 1920s and 1930s. For the 1940s and 1950s, the papers deal mainly with consulting. They consist of correspondence and reports for the Defence Department (1942- 1946), the Canadian Council on Nutrition (1946-1955) and the Canadian Council on Dietary Standards (1950-1957). Nutrition and research in this field are also the subjects of correspondence with the Royal Society, the Medical Research Council, and the Canada Council during this period. Thomson's work as a university teacher is documented by lecture outlines and examination question papers. His administrative positions led to his involvement in the National Council of Canadian Universities. These correspondence files (1946-1949) deal with academic exchange, scholarships, travel funds and conferences.

Speaking engagements are recorded by correspondence (1953-1954) and in drafts for speeches delivered between 1950 and 1961. Only a few of these discuss scientific topics; most discuss the nature of education, the relation of science to society, and of science to literature. There are also book reviews and background files of quotations and humorous poetry. Correspondence files, which Thomson generated as the Chairman of the Nutrition Committee of the Montréal Council of Social Agencies, are also found here (1939-1944).

Financial affairs, personal purchases and charities, travel expenses, and publications (particularly his Life of the Cell) dominate the private papers (1925-1963). There are also correspondence files maintained by Thomson's secretary during his last illness.