The First Genetic Map.

The 1910s saw important work in the biological sciences that often had both immediate and long-term consequences. Building on the base provided by the Austrian botanist Gregor Mendel, who in the mid nineteenth century had shown that "hereditary factors" in plants were passed on to their progeny in predictable ways, Thomas Hunt Morgan and his colleagues published the first chromosome map in 1911. The diagram identified the location of five sex-linked genes from the salivary glands of the fruit fly {Drosophila). Morgan found that the genes were arranged like beads on a necklace. In 1919 he published his Physical Basis of Heredity, and by the decade's end almost two thousand genes had been mapped, setting the stage for future advancements.

A Cure for African Sleeping Sickness.

Among the outstanding women scientists of the period was Louise Pearce, a Ph...