London: John Murray, 1890. Second edition , revised. Tenth thousand. Cloth. Two volumes, small octavo (5" x 7.5"), dark green cloth with gilt titles. Covers decorated in blind. xiv, 473pp,  with ad leaf; x, 495pp. with index. Illustrated with wood engravings. A tight, clean set with a minor rubbed spot on each spine. There is a faded area at the fore-edge of the cover of volume one. A very attractive set. Very good. Item #19325
The first appearance of the term pangenesis, in which Darwin postulated the existence of a hereditary material inside cells called gemmules which could be modified by the organism's environment and passed on to the offspring.