The collection includes letters between Hutchinson and his uncle Israel Pemberton, written while Hutchinson was a student of medicine in London. There are also 12 tickets of admission to medical lectures in Philadelphia and London, including one given by William Hunter, and 3 unused cards of admission to Hutchinson's own lectures. Miscellaneous items include Hutchinson's marriage certificate; genealogical data on the Hutchinson, Hare, and Pemberton families; and stock certificates, 1857-1872, of the McKean and Elk Land and Improvement Company. Materials dated post-1793 are to and from Hutchinson family members.

Born in Boston and educated there and in France, Samuel Breck (1771-1862) was a major figure in the mercantile, philanthropic, and political life of Philadelphia during the first hald of the nineteenth century. With an interest in historical and literary affairs, Breck was an active member of the Library Company of Philadelphia, the Phialdelphia Athenaeum, the Historical Society of Pennsylvania, and the American Philosophical Society (elected 1838). The Breck Collection is comprised of two manuscripts written by Samuel Breck. The first, "Historical Sketch of the Continental Bills of Credit, from 1775 to 1781, with Specimens Thereof" (1840), includes an essay and 153 specimens of Continental Currency. The second essay, "Recollections of My Acquaintance and Association with Deceased Members of the American Philosophical Society" (1862) includes the 92 year-old Breck's reminiscences of his personal relationships with the nationally and internationally prominent membership of the APS.

Though the Miscellaneous Manuscripts collection is composed of items that do not fall readily into any other existing collection, the two dominant intellectual areas represented in the collection are Early American History and History of Science.