The first part of the collection contains letters between Haldane from his mother, Mary Elizabeth Haldane (née Burdon Sanderson) and other family members regarding familial matters. These letters range from 1883 to1926. There are other letters pertaining to Mary Elizabeth Haldane and Edinburgh professors that are in the collection as well ranging from 1887 to 1922. Haldane’s personal documents, including his birth certificate and university certificates are also in this collection, ranging between 1878 to1897.

His reports, tables and correspondences are contained within, as well as his papers and speeches. These are largely undated and concern topics such as miners’ eye problems, tuberculosis in the Navy, regulation of normal breathing, functions of sweat, kinetic theory of gases, death by suffocation and the like. According to H.M. Sinclair: “Mrs. Haldane told me that her husband destroyed his MS as soon as the paper was published, and these lectures and addresses to various societies were not published. Haldane always wrote his addresses out in full, and this collection is mainly written in full in his own hand.”

A section of the collection contains reports and correspondence of Haldane’s work with the use of gas in WWI. H.M. Sinclair states that the collection is: “A most important collection of papers relating to his and Douglas's researches in World War I when gas was first used. Included are long autograph letters from Douglas (who was in the field in France), very out spoken about the military authorities and giving full descriptions of the casualties and attempts to prevent them.”

Finally, there are 2 drafts of an unpublished book written by Haldane on vitalistic physiology. H.M. Sinclair notes that: “The first draft is copiously corrected . . . This has been entirely rewritten in nine chapters of the final draft. . . . This very interesting book was never published, but illustrates the state of physiology at the turn of the century as seen by a young graduate of about 30 years.”