Digestion.- Pavlov (Ivan Petrovich) Die Arbeit der Verdauungsdrüsen, translated by Dr.A.Walther, first edition in German, lacking half-title, with graphs in text, 4pp. advertisements at end, contemporary half roan, [cf.PMM 385], Wiesbaden, 1898 § Beaumont (William) Experiments and Observations on the Gastric Juice, and the Physiology of Digestion, edited by Andrew Combe, half-title, traces of library stamps to title and final leaf, later cloth-backed boards, Edinburgh, 1838 § Tiedemann (F.) & Leopold Gmelin. Recherches Expérimentales, Physiologiques et Chimiaues sur la Digestion, 2 parts, first edition in French, half-title, errata leaf at end, tables, book-label of the nutritionist John Yudkin, contemporary roan-backed boards, spine faded, Paris, 1827, all rubbed; and 13 others on digestion, 8vo & 4to (16)

⁂ The first mentioned was first published in Russian in St.Petersburg in 1897 and appeared in English as Lectures on the Function of the Main Food-Digesting Glands in 1902. Pavlov observed that gastric juices in animals flowed upon seeing or smelling food which led him to develop the idea of the conditioned reflex, for which he was awarded the Nobel Prize for Medicine in 1905.
The second item was the most important study of digestion before Pavlov, by an American army surgeon, and first published in Plattsburgh, NY in 1833.