thought of being an artist, but attendance at a drug-store set him thinking of medicine, and in 1844 he graduated M. D. from the University of Pennsylvania, with a characteristic thesis on the "Comparative Anatomy of the Eye of Vertebrate Animals." In the same year he became prosector in anatomy at the university and demonstrator of anatomy in the Franklin Medical College, 1846. When the chair of anatomy became vacant at the university through the death of Dr. Horner in 1853, Leidy, who had acted as his assistant, was appointed. Thirty at the time, he held it until he was sixty-eight and "the lustre he threw on the university quenched all jealousies by its bright- ness."
To say that he was always at work would be as natural as to say a lover would be with his mistress; the joy of increasing knowledge overmeasured fatigue. Appointments and honors were multiplied: professor of natural history to Swarthmore College; presidency of the Academy of Natural Sciences; professor of zoology in the University of Pennsylvania; Harvard gave him her LL. D. He was honored by the Lyell medal from the London Geological Society and the Cuvier medal from the Paris Academy of Science. He was, besides, member, active or honorary, of over forty native and foreign societies. At the time of his death he had attained an enviable reputation as a mineralogist and botanist; was among the highest authorities on comparative anatomy and zoology; a distinguished helminthologist and paleontologist.
In 1864 he married Anna, daughter of Robert Harden.
Perhaps his wonderful monograph on "The Fresh Water Rhizopods of North America," the result of laborious research, best shows how loving a student he was, and his drawing and coloring of microscopic objects proved him also a real artist. As an anatomist, "nothing" says his collaborator Dr. Hunt, "could exceed the beauty of Leidy's dissections . . . the display of the diaphragm, the muscles of the abdomen and chest, the thoracic and abdominal viscera; the clear, concise explanation and exhibition of the human brain. I was with him also during many of his investigations particularly into the comparative anatomy of the liver, the development of the Purkinjean corpuscles in bone and that of the intermaxillary bone. Leidy's wonderful display of temporal bones is now in the museum. His description of the vocal membranes and larynx structures is admirable. His acquaintance with extinct forms of life was equally wonderful.
1846 marked his sure track concerning the origin and action of the Trichina spiralis of hog cholera, though the full significance of the parasite in the hog was not all at once apparent. The great German helminthologist Leuckart, Cobbold and others fully acknowledged the discovery as due to Dr. Leidy.
But the weight of his genius stays the pen. How to do justice in a few brief pages. " By his knowledge" says the giant lizard Hydrosaurus Foulkii "I was reconstructed." " By his knowledge of my life in prehistoric days the wonderful changes in my size from less to greater have been shown" echoes the Equus Americanus. Coming more to the human side of Leidy, savants and students, rich and poor and children all eagerly added their share of praise to the gentle-hearted scientist who received correction gladly but bestowed it on amateur scientists so modestly and sweetly that it never discouraged or hurt at all.
Here is one little intimate glimpse. He had a fine spirituelle face, curiously resembling pictures of the Saviour, and children noticed this. "One day Leidy was staying with a member of the Academy and the company started out for a walk. The host's little daughter suddenly broke away and ran over the grass in pursuit of a butterfly. After much exertion she caught it and whispered in her father's ear that it was 'for Jesus Christ' and timidly gave it to the doctor."
Early in April, 1891, hard work began
