To the Editor:—
In The Journal, Dec. 17, 1955, page 1525, is an article, "Radiological Diagnosis of Retained Surgical Sponges," by Drs. H. M. Olnick, H. S. Weens, and J. V. Rogers Jr. Dr. Nicolai Cahn of Berlin, Germany, first developed such radiopaque gauze and sponges 26 years ago. He reported on his invention at the 53rd convention of the German Surgical Association in Berlin in April, 1929. I published a paper on experiments with this radiopaque gauze used in surgery in the Zentralblatt für Gynäkologie in 1930, pages 2839-2844.