Merrival Fanning Dumas, M.D. also known as M.F. Dumas was the first doctor  resident in Bald Knob; He was the only doctor in 1880. He was the mayor of Bald Knob in 1881.
 

His half brother, Lawrence Jefferson Dumas - He was the first druggist resident in Bald Knob, coming between 1877-79.
 

About the same time:
William 'Will' Alexander Clark, M.D. - 1889 - He came to Bald Knob and opened an office. He was a doctor in Bald Knob for 47 yrs
His brother Robert 'Bob' Cook Clark - He came in 1900. He had three drug stores. One was in Little Rock. (They are still in the family).

Dr. Will Clark came in 1889 and was in business by 1890 and Bob Clark came in 1900 and was in business that year and they were parallel with the Dumas brothers, Dr. M. F. and Lawrence J. Dumas as doctor and druggist (the Dumas brothers arrived about 1878 and set up business that year.)

 
Both Clark brothers were Town Council Members in the early 1900's.

A history book (Tales from the Big Rock?) notes that the Dumas Brothers (Lawrence J. and Dr. M.F.) and the Clark Brothers (Robert C. and Dr. Will A.) were pharmacists and doctors at the same (pioneering days) time - the turn of the century - one each in each family. The families probably knew each other well.