1901-1907 Two parts in two. 1,236 [x, 160; xvi, 944, cviii] p., 23 plates and maps, near uniform half cloth (one brown, one dark blue) over marbled boards. Gilt title on spines. A very detailed study with numerous data from new experiments and records of relevant previous studies. Rare. Neither in Horn-Schenkling nor in Hagen, nor in Cat. BM(NH). Two small cut-outs on the title pages and one clipping in front flyleaf, all without touching the text.