Hermann von Helmholtz, the great German physiologist and physicist, and Frau von Helmholtz are seated in the center, on the left is Professor Hugo Kronecker, of Bern, the distinguished physiologist, whose death recently occurred. In the center is Mr. Henry Villard; on the right, Dr. T. C. Mendenhall, the American physicist. We owe the photograph, which was taken in Washington in 1893, to Dr. S. J. Meltzer, of the Rockeffeller Institute of Medical Research, a student and friend of Kronecker's.