Mineral water was discovered entirely by accident on Sylvanus Barnard's West Morgan Street property in 1887 when workers drilled a well in the hope of locating gas or oil. Barnard and the other investors were disappointed by the discovery of a large vein of foul-smelling water instead of a fuel source, but as soon as word spread throughout southern Indiana that mineral water had been found, people flooded to the well with water jugs and cups. The mineral water was thought to cure major and minor diseases and disorders, including acne, depression, impotence, constipation, kidney and bladder diseases, stomach ailments, and rheumatism.

     In 1888 Sylvanus Barnard built Martinsville's first sanitarium, the Barnard Sanitarium. The spa provided services for men and women, but it did not contain sleeping rooms. Out-of-town guests were forced to rely on local boardinghouses and hotels for accommodations. Despite this oversight, the spa was so busy that Mr. Barnard enlarged and renovated the building after only one year. The Barnard Sanitarium attracted a loyal clientele composed mainly of working-class and middle-class Midwesterners.

     The business remained in the Barnard family until 1924, when Sylvanus' son Henry Barnard sold it to Dr. O.M. Carter and Charles Grayer of Monticello, Kentucky, and Ed Hubbard of Martinsville. One year later the spa was returned to the Barnard family. Gene Barnard, who had managed the spa, sold the business to local entrepreneurs David and Michael Cohn in November 1926. The Cohns also ran the Hill-Cohn Sanitarium and later purchased the Colonial Mineral Springs in Martinsville. The Cohns operated the spa under the name the Cohn-Barnard Sanitarium.

     A fire destroyed the building in 1940. Instead of rebuilding the sanitarium, the Cohns purchased the Colonial Mineral Springs on West Washington Street in Martinsville shortly after the fire and renamed it the Cohn-Barnard Sanitarium. This has understandably caused much confusion over the years, and people began referring to the first Cohn-Barnard as the Old Barnard to distinguish it from the later one.

     The site of the Barnard Sanitarium is currently occupied by the John Hubler Chrysler-Dodge dealership near the town square.