In 1839-1840, the ichthyologist Richard Parnell left London for a collecting expedition to Jamaica and a tour of museum collections in the United States. An authority on both fishes and grasses, Parnell published two noted works as a young man, his Prize Essay on the Natural and Economical History of the Fishes Marine, Fluviatile, and Lacustrine, of the River District of the Firth of Forth (Edinburgh: Neill and Co., 1838) and The Grasses of Britain, 2 vols. (Edinburgh: Blackwood, 1842-1845). He appears, however, to have abandoned publication in 1845, although he continued collecting for many years. The notebook kept by Richard Parnell during his voyage to the West Indies and United States in 1839-1840 contains little narrative, but dozens of pencil and watercolor sketches of the marine life that absorbed his interest, primarily fishes. Most sketches are accompanied by brief notes on the anatomy of the fish, sometimes with close-ups of fin structures, air bladders, or the digestive tract and stomach. Although collecting localities are seldom recorded, the majority of specimens seem to have been collected in Jamaica, with at least a few observed in vitro at the New York Museum.

A member of a family of early 19th century artists and instrument makers that included Cornelius, John, and William Fleetwood Varley, Cromwell J. Varley shared in the family interests in astronomy. The Journal of Astronomical Observations includes brief notes on telescopic observations of comets, stars, and planets conducted by Cromwell J. Varley between 1845 and 1858, accompanied by twenty ink and watercolor sketches.

Through his craniometic studies of human races, the Philadelphia physician Samuel George Morton (1799-1851) exerted a profound influence on the development of physical anthropology in antebellum America, and made substantial contributions to mineralogy, paleontology, and natural history. Relating primarily to Morton's scientific interests, the Morton Papers include insights into Morton's perspectives on education, medical practice, geology and mineralogy, craniology, paleontology, the Wilkes Exploring Expedition (also known as the United States Exploring Expedition 1838-1842), and his two major monographs, the Crania Americana and Crania Aegyptiaca. Several of the letters were written by Morton in his capacity as corresponding secretary of the Academy of Natural Sciences of Philadelphia. Also included in this collection are Morton's "Some Remarks on the Infrequency of Mixed Offspring Between the European and Australian Races" (1850), Joseph Barclay Pentland's notes on the aborigines of Peru (ca. 1840?), and newspaper clippings on Morton's death; a diary of Morton's trip to the West Indies, 1834, a set of craniological sketches for use in Crania Americana, and a microfilm of letters in private hands, written to Morton, 1838-1844

A physician, natural historian, and professor at the University of Pennsylvania, Benjamin Smith Barton (1766-1815) was one of the central figures in Philadelphia's early national scientific establishment. Having received his medical training in European universities, Barton was appointed Professor at the University of Pennsylvania in 1789, lecturing on botany, materia medica, natural history. A prolific author, he established his reputation as one of the nation's preeminent botanists through his botanical text book The Elements of Botany (1803), but his contribtions to zoology, ethnology, and medicine were equally noteworthy. Barton's monograph on the "fascinating faculty" of the rattlesnake and his efforts in historical linguistics (New Views of the Origin of the Tribes and Nations of America, 1798) were widely read, and his Philadelphia Medical and Physical Journal (1804-1809) was one of the nation's first medical journals and an important outlet for natural historical research. The Barton Papers offer a comprehensive view of the professional work of Benjamin Smith Barton from the time of his return to the United States in 1789 until his death. The collection is divided into five series: Correspondence, Subject Files, Bound Volumes, Graphic Materials, and Printing Plates. The collection includes a particularly valuable series of botanical, medical, and natural historical drawings collected by Barton for research, reference, and publication. Among the many artists represented are William Bartram, Frederick Pursh, Pierre Turpin, and Benjamin Henry Latrobe.