Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Portrait of Galen of Pergamon (131–200 AD). He wrote extensively about the pulse and used it for both the diagnosis and predicting the prognosis of disease. Source: National Library of Medicine (the history of medicine public domain image files). Lithograph by Pierre Roche Vigneron (Paris: Lith de Gregoire et Deneux, ca. 1865).
