Harold C. Riethman, Ph.D.

The microscope in the image belonged to William E. Horner, M.D., a collaborator with Caspar Wistar, M.D., in the early 1800s.

Dr. Horner, a lecturer at the University of Pennsylvania, was a pioneer of the use of microscopes in anatomical and medical research. He authored Special Anatomy and Histology, a seminal text on the subject.