The correspondence (1869-1883) is primarily routine business, i.e. navy orders and letters of recommendation, and also includes some personal letters. In addition, there are several notebooks and diaries, including notes from Pennsylvania Hospital clinical lectures, 1867-1869 (2 v.); diaries, 1865-1875 (7 v.); a volume of poetry; and general study notes. There is also early material (1745-1813) on the Cassin family, including a letter of indenture dated 1758.