PURKINJE, Jan Evangelista (1787-1869) & Gabriel Gustav VALENTIN (1810-1883). De phaenomeno generali et fundamentali motus vibratorii continui im membranis cum externis tum internis animalum plurimorum, Breslau: A. Schulz, 1835, 4°, FIRST EDITION (spotted), contemporary boards (covers detached, spine split) [GM 602: "classical paper on ciliary epithelial motion"; Norman 1766] -- Johannes MÜLLER (1801-1858). Über die Compensation der Physischen Kräfte am Menschlichen Stimmorgan, Berlin: 1839, 8°, 4 folding engraved plates (browned, title and one text leaf blind-stamped, earlier library stamp excised from title with loss of text, title on guard), contemporary cloth-backed boards (rubbed, joints split). [GM1458; Osler 3468; Waller 6732] Provenance: Berlin Collection (2)