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 in the United States, the Johns Hopkins School of Hygiene and Public Health. He was Dean of the School of Hygiene (now Bloomberg School of Public H