The following words and terms, when used in these sections, shall have the following meanings, unless the context clearly indicates otherwise:(1) Department--The Department of State Health Services, 1100 West 49th Street, Austin, Texas 78756.(2) Unit--The Immunization Unit, Infectious Disease Prevention Section, Department of State Health Services.(3) Physician--A physician (medical doctor or doctor of osteopathic medicine) licensed to practice medicine in the State of Texas.(4) Vaccination Center--The location where a physician is authorized to administer yellow fever vaccine.(5) Uniform Stamp--A stamp issued by the unit to a physician for use in validating certificates of yellow fever vaccination for persons who travel outside the United States.