Dr. Donald Slaughter taught pharmacology at Southwestern Medical College and was also Dean of Students. In this photo he studies the output of a physiological process on a kymograph, which consists of a revolving drum wrapped in a sheet of paper on which a stylus moves back and forth. At the time this photo was taken, kymograph paper was covered in charcoal, which is why the paper looks black except where the stylus has touched it. The primary use of a kymograph was to measure physiological processes. This was digitized from the 1945-46 Southwestern Medical College yearbook, “Caduceus.”