William Henry Howell
William Henry Howell, Ph.D., M.D., LL.D., Sc.D. (20 February 1860 – 6 February 1945) was an American physiologist. He pioneered the use of heparin as a blood anti-coagulant.

William Henry Howell was born in Baltimore, Maryland and graduated from the Baltimore City College high school in 1878. He was educated at Johns Hopkins University, from which he graduated in 1881.  He taught at the University of Michigan and at Harvard before becoming professor at Johns Hopkins in 1893.  He was dean of the medical school from 1899 to 1911. He resigned that position to help William Henry Welch and others to establish the first graduate school of public health, the Johns Hopkins School of Hygiene and Public Health.  He was Dean of the School of Hygiene (now Bloomberg School of Public Health) from 1926 to 1931.

Howell contributed to the London Journal of Physiology, the Transactions of the Royal Society, the Johns Hopkins Biological Studies, the Journal of Morphology, and the Journal of Experimental Medicine.  He was associate editor of the American Journal of Physiology after 1898.  He wrote Text-Book of Physiology (1905; fifth edition, 1913). And this was a standard text book for medical students for the next 50 years.