1900
Major blood types identified.
1903
Birth of the RN credential in the U.S. with the establishment of the first state boards of nursing in North Carolina, New York, New Jersey, and Virginia.
1909
Red Cross Nursing Service organized; Jane Delano appointed chief.
1911
American Nurses Association founded out of the Associated Alumnae of the U.S. and Canada


1914
Margaret Sanger opens first birth control clinic.
1917
Formation of the Army School of Nursing.
1918
Great influenza epidemic; 500,000 die in U.S.
1918-19
25,000 nurses serve in WW I; reconstruction aides, precursors to OTs and PTs, treat the war wounded.
1920
19th Amendment passes; women get the right to vote.
1925
Mary Breckenridge founds the Frontier Nursing Service; American Academy of Speech Correction established, introducing the practice of speech-language pathology.
1935
Social Security Act passes.
1940
Formation of the Nursing Council for National Defense.
1941-45
World War II, 75,000 to 78,000 nurses serve; black nurses refused admission into the Army until 1944; men refused admission as nurses.
1943
Formation of the U.S. Cadet Nurse Corps; 123,000 nurses trained. Pap smear introduced.
1944
Black nurses inducted into the Army after a struggle.
1946
Hill-Burton Act passes; more hospitals are built. Constitution of the World Health Organization approved.
1947
Inhalation Therapy Association forms, marking the birth of respiratory therapy as a profession.
1955
Mass immunization for polio begins.
1956
Health Amendments Act passes, beginning aid to nursing schools.
1958
First patient revived by CPR.
1964
Civil Rights Act passes; Federal Nurse Training Act passes, starting chain of educational aid that lasted until the '80s.
1965
Medicare and Medicaid introduced.
1977
Last case of smallpox recorded.  
1978
Louise Brown, first test tube baby, born.
1983
Diagnosis related groups (DRGs), a new hospital payment system, debut.
1986
National Center for Nursing Recruitment finds a place at the NIH.
1987
Universal precautions introduced.
1997
Balanced Budget Amendment passes, cutting funding to programs in which Medicare plays a significant role.
PHOTOS, FROM TOP: AMERICAN RED CROSS (FIRST THREE), CORBIS, STANFORD MEDICAL CENTER, AMERICAN PHYSICAL THERAPY ASSOCIATION, CORBIS (LAST TWO). BACKGROUND PHOTOS, LEFT TO RIGHT: DIGITAL STOCK, PHOTODISC (AMBULANCE, STETHOSCOPE), COMSTOCK ©1999