Nellie Cecilia Hartmann was born August 24, 1910 at St. Mary's, Missouri, she was the eighth child of William Joseph and Evalice (Beis ) Hartmann. Her early schooling took place in the district school of the locality. After her freshman and sophomore years at Lafayette High School in Lafayette, Illinois, Nellie completed her junior, and senior years, plus a business course, at St. Joseph's Academy, Clyde, Missouri. This was her first encounter with the Sisters she chose to live with the rest of her life.

At the age of seventeen, she applied for admittance and started the postulancy on July 28, 1927. On March 10, 1928, she became a Novice, under the direction of Sister M. Carmelita Quinn. During the years of formation she also took a correspondence course from the State Teachers College in Maryville, in "Principles of Teaching.”

When on September 1, 1929, Nellie made profession of first vows, together with Sr. M. Crescentia Mueller, Geraldine Hutchinson, Hilda Mary Simon, Adela Blatt and Genevieve Stoecklein, she received the name Sister Mary Incarnata. Her patron was Jesus, Incarnate Word, and her feast, the Annunciation, March 25.

Sister M. Incarnata remained at Clyde, working in the correspondence department, and helping with building maintenance until after she made final vows, October 27, 1934. Her first transfer came in February, 1936, when she was sent to the foundation recently begun in Tucson, Arizona. She remained there until May 25, 1943, then returned for a few months to Clyde. In November 1943, she became a pioneer in Kansas City, Missouri, at the Rock Hill address, and served as community treasurer. She took a course in architecture to help in the planning of the permanent chapel and convent. In the Kansas City Holy Spirit Chapel, she received Consecration as a virgin, April 6, 1953.

The short-lived experiment at San Benito, California also knew Sr. M. Incarnata as one of the pioneers. Then October 18, 1957, she became a member of Our Lady of the Blessed Sacrament convent at Mundelein, Illinois, but remained only one year. October 8, 1958 found her back in Kansas City, her expertise and talents challenged as she assisted Mother M. Carmelita Quinn in drawing up plans for a permanent chapel and convent in San Diego, California. Becoming a member of the San Diego community, she had resided there a little over six years when, on January 4, 1964, she was recalled to Clyde to help plan the Generalate and Formation house in St. Louis. At its opening, April 28, 1966, she became a pioneer member, serving as procuratrix and economa. She also worked on renovation plans in the completion of the unfinished wing in Kansas City.

The last fourteen years of her life were spent in Clyde. She celebrated her Golden Jubilee September 1, 1979 with her profession companions from the several convents at St. Louis for the occasion. At Clyde, she was manager of the altar bread department for a number of years, up to January 1982. It was at this time that the doctors discovered the cancer that changed her life of service into a mission of suffering.

By her spirit of acceptance, Sister was an inspiration to the community, to doctors and to her family. Death came peacefully early the morning of June 2, 1983. She was conscious to the last. Many Sisters were present, as also her own sister, Alma. The Eucharist was celebrated for her on Saturday, June 4, and her body was laid to rest in Mount Calvary cemetery.