COHEN, E. Das Lachgas. Eine chemisch-kulturhistorische Studie. Lpz., W. Engelmann, 1907. (8), 99, (1) pp. W. 31 ills. & 1 fold. cold. caricatural plate by Gillray. Or. printed wrps. (Spine rep. w. cloth strip, loose in binding, quires loose, w. stamp). With author's autograph dedication to J. Roëll on front cover. -- And 2 o. (3).