In these exciting times when elementary and high schools teach modern biology, including many of the intricacies of biochemical genetics, the long slow process by which our present knowledge in this area was gained is not often fully appreciated. A third of a century elapsed before Mendel’s work was "rediscovered" and properly appreciated. Archibald E. Garrod’s (1) prophetic appreciation of the relation genetics and biochemistry, beginning soon after the so-called rediscovery of Mendel, lay fallow for more than forty years despite the fact that he published widely and relatively voluminously. As late as a quarter of a century after the Mendel work came to light, Harvard’s distinguished professor of biology, William Morton Wheeler (2), ridiculed genetics as a small bud on the great tree of biology, a bud so constricted at the base as to suggest its eventual abortion. Wheeler’s colleague in paleobotany, Jeffrey (3), also expressed his disbelief in the work of the then flourishing school of Drosophila genetics. Fortunately, neither succeeded in significantly retarding the rapid advances then being made, many of them by two Harvard contemporaries, Edward M. East and W. E. Castle. It is of interest to note that Thomas Hunt Morgan (4) remained a skeptic about Mendelian interpretations for the first ten years after the rediscovery, that is until he established the sex-linked nature of the white eye trait in Drosophila.