These two letters exchanged between Edison and Lillia W. D. Trask, librarian of the Rockefeller Institute for Medical Research, are from November 1916. The letters concern a list of fluorescent salts that Edison apparently published in 1895. Trask forwarded Edison's letter to James B. Murphy, a pathologist in charge of cancer research at the Institute, who was studying the effects of x-ray radiation on living tissue.

An online finding aid to the archival collection is available.