Organ-forming substances in the eggs of ascidians by Conklin, Edwin Grant - 1905

Chicago: The University of Chicago, 1905. First edition.

1905 E. G. CONKLIN--LANDMARK EARLY STUDY OF EMBRYONIC DEVELOPMENT WITH ACTUAL PHOTOGRAPHIC PLATE BY PIONEER AMERICAN ZOOLOGIST AND EVOLUTIONIST--INSCRIBED AND SIGNED BY HIM.

10 inches tall offprint, gray printed wraps, inscribed, "Dr. Robt W. Hall/ with the compliments/ of E.G. Conklin." pages 205-230 reprinted from Biological Bulletin Vol. VIII, March, 1905 with glossy actual gelatin silver photographic plate containing 24 photomicrographs of the first stages of the developing embryo of a marine invertebrate. Light browning of covers, edgewear, top of spine chipped, text and plate unmarked, very good.

Conklin concludes, "These facts point to the conclusion that the complex organization of an egg, such as that of an ascidian, has not arisen through the 'reflection of adult characters upon the egg,' but rather that this organization is primary. Furthermore they seem to indicate that evolution has taken place, not through modifications of adult structure, but through changes in germinal organization; modifications of the organization, however produced, are probably the real causes of evolution." Written less than 50 years after Darwin's Origin of Species, this encapsulates the future rise of evolutionary developmental biology ("evo-devo") in the late 20th century.

EDWIN GRANT CONKLIN (1863-1952) was educated at Ohio Wesleyan University and Johns Hopkins University. He was professor of biology at Ohio Wesleyan (1891–94) and professor of zoology at Northwestern University (1894–96), the University of Pennsylvania (1896-1908), and Princeton University (1908-1935). He became coeditor of the Journal of Morphology, The Biological Bulletin, and the Journal of Experimental Zoology. He was president of the American Society of Naturalists in 1912 and president of the American Association for the Advancement of Science in 1936. He was elected a Fellow of the American Academy of Arts and Sciences in 1914. He also served on the board of trustees for Science Service, now known as Society for Science and the Public, from 1937-1952. In 1943 Conklin was awarded the John J. Carty Award from the National Academy of Sciences.