David B. Marshall received an excellent education at Mount Airy Academy, and in early manhood entered the office of his father as a student of medicine, attended lectures in the medical department of the University of Pennsylvania, from which institution he graduated in the spring of 1844. After graduation he began the practice of his profession in connection with his father at Annville, where he remained three years, subsequently practicing at Reading one year, when he permanently located at Lebanon. He soon acquired an extensive and lucrative practice, and took high rank in the profession. Endowed with strong natural talent, good judgment, and strong powers of observation and application, he needed only the opportunities which a large practice gave him to enable him to prove his ability as a practitioner, and to maintain a firm hold upon the affections of the people with whom he came in contact, and among whom he labored. He died in the prime of life. Possessed of a generous nature, he was greatly esteemed and respected by all, and his loss deeply lamented in the community as that of a valuable and upright citizen.