Des Moines, Iowa, March 9, 1896.
To the Editor:
—I have taken considerable interest in the published reports of the penetration of Roentgen's X rays and the application of the discovery to surgery; as well as to reports of similar results without the use of Crookes tubes. By virtue of accident I can report similar result independent of Crookes tube, dynamo, or any other agent of electrical light or force, so far as I know. Some months ago I placed a piece of sensitized paper in a book and it was forgotten. When discovered a few days ago, the page of the book was clearly and legibly printed upon the sensitized paper, as a positive. The discovery was so bewildering that I did not think of fixing it at the time, but next morning, when I went to do so, the image had vanished, and I lost the evidence of