From the beginnings of the Continental Navy in October 1775, doctors were included as an integral part of ships’ crews.  With the formal establishment of the U.S. Navy at the end of the 18th Century, physicians such as this continued to go to sea, although usually under contract for a specific cruise.  Although considered “officers” as of 1835, it wasn’t until 1871 that doctors were given commissioned ranks equal to those of line officers.