1850s: American social reformer and feminist Amelia Jenks Bloomer initiates "bloomer" fashion when she starts wearing full-cut pants under skirts. Bloomers enable women to move more freely and comfortably than did petticoats.

Today: Just about anything goes in the world of fashion for women—from conservative business suits and low heels to revived mini-skirts and tall black boots to the ever-present blue jeans, sweat shirts, and sneakers. "Bloomers" are an option, not a must, for some.

1850s: Florence Nightingale takes London nurses to the battlefields of the Crimean War, a conflict pitting Britain, France, and Turkey against Russia when the latter tries to advance into Turkey. Nightingale organizes a barracks hospital in a war that will claim more lives through disease than combat.

Today: Women still make up the great majority of the nursing field, but they are also increasing their numbers as physicians...