In 1914, Van Slyke was appointed chief chemist of the newly founded Rockefeller Institute Hospital, where he played a key part in developing the field of clinical chemistry.[3] His work focused especially on the measurement of gas and electrolyte levels in tissues,[1] for which he is considered to be one of the founders of modern quantitative blood chemistry.[3] He is also considered by many to have first popularised the term "clinical chemistry" in his two-volume work Quantitative Clinical Chemistry, co-published with John P. Peters. The two-volume work was widely accepted in the medical world as the "Bible" of quantitative clinical chemistry.[1] During this period, he also served as managing editor of the Journal of Biological Chemistry from 1914 to 1925.