Davis was the first to state that phlegmasia alba dolens was due to inflammation of the veins. He was physician-accoucheur at the birth of Queen Victoria.

Davis introduced a number of improvements in instruments and techniques: “It outlines rules and precautions for undertaking operations, described the use of various forms of forceps, and provided twenty detailed plates, [some of them] illustrating techniques of craniotomy using the crochet and Denman’s perforator” (Woods, Death before birth: Fetal health and mortality in historical perspective, p. 138).
Davis was appointed Royal Accoucheur in 1819, and attended the Duchess of Kent when she gave birth to the future Queen Victoria. This work is beautifully illustrated with double-page lithographed plates of the highest quality, and is an early example of lithography in medical illustration. The pioneering firm of Hullmandel printed most if not all of the plates; some are after drawings by William Clift, who was associated with the Hunters and did the illustrations for Baillie’s pathology atlas.