Charles Lester Leonard came of old New England ancestry, being directly descended from John Leonard who settled in Springfield, Massachussets, in 1632. His parents were M. Hayden Leonard and Harriet E. (Moore) Leonard of Easthampton, Massachussets, where he was born.
He graduated from the University of Pennsylvania in 1885 (A. B. ), from Harvard in 1886 (A. B. ), and from the Medical School of the University of Pennsylvania in 1889 (M. D. ). He studied abroad from 1889 to 1892 and received the degree of master of arts from his Alma Mater in 1892.
After beginning his medical practice Leonard inclined toward surgery and was connected with the surgical staff of the University Hospital, Philadelphia, mainly as anesthetist. Possessed of a scientific and technical mind, he became intensely interested in the X-rays in 1896, very soon after their discovery and announcement by Roentgen ("Cases Illustrative of the Practical Application of the Roentgen Rays in Surgery, " in collaboration with J. W. White and A. W. Goodspeed, American Journal of the Medical Sciences, August 1896).
At the time, the X-rays were regarded as of service only in the detection of fractures and opaque foreign bodies such as bullets. Leonard was the first, in America, at least, to demonstrate the presence of stones in the kidney and other portions of the urinary tract by means of this agent (1898). This demonstration at once gave him world-wide publicity in the medical profession, especially among those beginning to specialize in this new branch of medicine. His ability to detect stones and his powers of observation and interpretation at that time were almost uncanny. He saw what others could not see, even when it was pointed out to them, and he was usually correct in his deductions. Throughout the early years of his experience he worked with small and what now seems most inefficient apparatus, but he was able to do more with little than almost any other man in his specialty. He was, indeed, a master of his art.
Leonard was a prolific writer, an untiring student, and a generous teacher of pleasing personality who was always ready to share his knowledge with his professional colleagues. He was an active member of the American Roentgen Ray Society and its president in 1904 and 1905, and was the founder of the Philadelphia Roentgen Ray Society. He was keenly interested in many other medical societies and a frequent contributor to their scientific programs.
In 1902, he resigned from the University of Pennsylvania and engaged thereafter in the private practice of his specialty. As a result of excessive exposure to X-rays from the unprotected tubes of the early years and the frequent use of the fluoroscope to test the tubes and to demonstrate his hands to those interested, he soon developed the chronic skin affections which attacked the hands of so many of the early workers who knew nothing of the dangers of the rays. He refused surgical treatment until it was too late, largely because, like so many others then, he regarded the condition as harmless and likely to heal after protective measures were devised. In the latter years of his life he was a constant but uncomplaining sufferer, never allowing his affliction to interfere with his duties. Those who knew him well marveled at his fortitude. Some of the chronic ulcers on his hands eventually induced cancer, which spread to other parts of his body, and from which he died--a martyr.
His last paper, "Radiography of the Stomach and Intestines, " was a review of all the literature on the X-ray examination of the stomach and intestinal tract, up to 1913, prepared for the International Congress of Medicine, London, August 1913. Since he was unable to attend, it was read for him by a colleague, and was published in the American Journal of Roentgenology, November 1913, after his death.
Leonard will always be remembered as one of the pioneer Roentgenologists of the United States. He successfully reproduced a stereoroentgenogram of the small intestine and he was the first to identify kidney stones in a skiagraph. In the thirteen years of his practice of Roentgenology he also published forty-four articles on the diagnostic uses of X-rays and their application in the treatment of cancer and other conditions.
Member of the American Roentgen Ray Society
Leonard married Ruth Hodgson, by whom he had one daughter.
