Surgeon at the Pennsylvania Hospital and later in the U. S. Navy, Barton taught Botany at the University of Pennsylvania and Materia Medica at Jefferson Medical School. This letter transmits through a common friend, Mr. Vaughan, a copy of Barton's Vegetable Materia Medica (publ. 1817-18) with 50 uncolored plates and apologies for them being uncolored because the coloring was not up to the quality of Michaux's plates, and promises colored ones in the spring. On an inside page of the letter is an annotation by George Ord, April 14, 1845, stating that the above book and letter were found in the Hall of the American Philosophical Society, left there by the late librarian, J. Vaughan.