A member of the National Academy of Sciences, he was known for his 1874 text Treatise on Therapeutics, which became a widely used medical textbook, and also for his botanical and zoological work: writing on freshwater algae, fossil plants, arachnids, and myriapods.

[3] The family were Philadelphia Quakers descended from Richard Wood who sailed from Bristol with William Penn.

[3] Wood started studying medicine at the Medical Department of the University of Pennsylvania in 1859, and graduated in 1862, having presented a thesis on "enteric fever".

[3] While still a student, Wood wrote his first scientific paper, reporting on the Carboniferous flora of the United States.

[6]: 7  Species named by Wood include Scolopendra polymorpha, the giant desert centipede, and Harpaphe haydeniana, the yellow-spotted millipede.

[3] Wood was the editor of several scientific journals, including New Remedies (1870–1873), Philadelphia Medical Times (1873–1880), The Therapeutic Gazette (1884–1890) and the U. S. Dispensatory (1883–1907).