Born in Maryland to Quaker parents who were strong abolitionists, Mary and her two sisters grew up believing in the value of all people.  The family lived for a time in Washington D.C. and her father took Mary to hear debates in Congress, sparking an interest in politics.  While still in her teens the family moved to New Lisbon, Ohio where she met and married Dr. Owen Thomas, also a Quaker.

Mary studied medicine with her husband in Wabash County, Indiana, then attended a course of lectures in the Penn's Medical College for Women in Philadelphia in 1851-52, another course in Cleveland Medical College in 1852-53, and returned to and graduated from Penn's in 1854.   After practicing for two years in Fort Wayne, she and her husband moved to Richmond, where she remained for the rest of her life.  During the Civil War she took part in the work of the Sanitary Commission and, by direction of Governor Oliver P. Morton, carried supplies to the front by steamer. On the return trip she nursed soldiers wounded at the battle of Vicksburg.  She later served as an assistant physician with her husband, an army contract surgeon, in a hospital for refugees in Nashville, Tennessee.  After the war she served on Richmond's board of public health, and from 1867 until her death she was the physician for the Home for Friendless Women in Richmond.  She was elected a member of the Wayne County Medical Society in 1875, after having been rejected twice because of her sex.  She became the first woman member of State Medical College in 1876.  In 1877 she was a delegate from the State Medical Society to the American Medical Association, and was the second female physician admitted to membership of that body. 

In addition to her medical career, Mary was very much involved in working for women's rights beginning in 1845 when she heard Lucretia Mott preach at a Quaker yearly meeting in Salem, Ohio.  She was a member of the Indiana Woman's Rights Society, serving as president in 1856.  In 1857 she edited the Lily, a woman's rights paper begun by Amelia Bloomer.  In 1859, she became the first woman to address the Indiana State Legislature by presenting a petition calling for a married women's property law and a woman suffrage amendment to the state constitution.   Her presentation was not taken seriously by the legislature, however.  After the Civil War she again worked for suffrage and became president of the Indiana Woman Suffrage Association. She even served a one year term as president of the American Woman Suffrage Association. 

Mary Thomas died on August 19, 1888 and had designated that her pall bearers all be women; four white women representing the Good Templars, the Woman's Christian Temperance Union, the Woman's Suffrage Association and the Home for Friendless Women, and two African-American women "to represent the Abolition cause and their race." (Richmond Daily Telegram, 21 Aug 1888)

History of Wayne County, Indiana. Chicago: Inter-State Publishing Co., 1884: 606-608.   [Adult Non-Fiction  977.263 I61a2]

Scholten, Pat Creech.  "A Public 'Jollification': The 1859 Women's Rights Petition before the Indiana Legislature."  Indiana Magazine of History 72 (December 1976): 347-359.

Pamphlet File in Morrisson-Reeves Library.

From Directory of the City of Richmond, 1857