"A Dictionary of Thoughts: Being a Cyclopedia of Laconic Quotations from the Best Authors of the World, Both Ancient and Modern" by Tryon Edwards, New York, Cassell publishing company, (p. 212), 1891.
Sir William Osler, Mark E. Silverman, T. J. Murray, Charles S. Bryan, American College of Physicians--American Society of Internal Medicine (2003). “The Quotable Osler”, p.38, ACP Press