Du Bois-Reymond’s major work containing the body of his physiological studies and research. The first volume appeared in 1848 and the first part of the second volume in 1849. The second volume was not completed until 1884 after additional years of research and experimentation. Because of the long interval between publication of the individual volumes, complete sets are very rare. The plates were drawn by Bois-Reymond and engraved by C.E. Weber. The great work for which Du Bois-Reymond became widely known at a young age was Untersuchungen über thierische Elektricität. In the famous foreword he expounds his ideas on the innermost essence of vital phenomena, and probably the weaker sides of the vitalistic theory had never before and seldom since been subject to such keen and striking criticism as here. The old life-force is reviewed from all sides and the arguments in its favour are refuted one after another. His most important discovery in the field of electrical phenomena in the animal kingdom is the fact that the muscles and nerves of animals during their state of activity produce electric currents which can be observed and measured with the aid of the usual apparatus of electro-physics. Students, co-workers, and visitors from all over the world took up electrophysiology, improved the measuring devices, and demonstrated electrical phenomena in glands, the eye, the heart, and the brain. In this way, new areas of physiology originated from his preliminary work. Du Bois-Reymond significantly affected his own time and posterity on two levels. In electrophysiology he laid the foundations of the methods that were to be applied for a century. In his treatment of problems of scientific boundaries and principles, he developed such brilliant formulations that his arguments still arouse great interest. Collation: Vol. I. (1848): pp. lvi, 743, (1) errata. With 6 folding engraved plates. Vol. II:1 (1849): pp. (6), 608. With 4 folding engraved plates (numbered I-IV). Vol. II:2 (1860): 384 (of 579). One folding engraved plate (of two) numbered V. This set contains the first 24 sheets of vol. II:2 (pp. 1-384) and plate V. The remaining sheets (pp. 385-579) and plate VI, were not issued until 1884, and are missing in this set. Binding: Two volumes. Contemporary half calf, richly gilt spines (very worn), marbled boards. References: DSB, IV, pp. 200-03 (by K.E. Rothschuh); Nordenskiöld, pp. 411-13; Brazier, A History of Neurophysiology in the 19th Century, pp. 71-9; Rothschuh & Risse, pp. 220-214; Haymaker, The Founders of Neurology, pp. 116-19; Hagelin, Kinetic Jottings, pp. 158-9. Waller 2599 (vols. I-II:1 only).