London: John Murray, 1868. FIRST EDITION, FIRST ISSUE. With several text illustrations. Original publisher's green cloth, a few small bumps, minor wear to boards; approximately 2 inches of the top of the fly-leaf of both volumes cut out. Generally a very nice set, uncut, with the presentation bookplate of the University of Southern California Messrs. Milton and Stanley Slotkin in each volume, ownership signature on the title to Volume II. Item #13360
First edition, first issue of Darwin's great contribution to the descent theory, and the foundation on which all later racial-biological research was based. This work expands in detail material that Darwin had intended to include in his Origin. The most novel element in the work is Darwin's hypothesis of pangenesis, by which he attempts to explain hereditary resemblance, inheritance of acquired characteristics, atavism and regeneration. Although proven invalid, this theory was nevertheless of prime importance in the history of genetics. "Darwin carried out numerous investigations with pigeons and various plants. He recognized continuous and discontinuous variation; he concluded that crossing tends to keep populations uniform" (G&M).