. B . S . Haldane ( 1949 ) on Infectious Disease and Evolution

HARLES Darwin was gratefully aware of the adC vances in microbiology and infectious disease (ID) associated with his contemporaries, Louis Pasteur and Robert Koch. Nevertheless, in none of his works does he make substantial mention of the role of ID as a driving force in natural selection. In contemporary observation, this seems self-evident, with frequent decimation of species by ID: viruses, bacteria, protozoa, or fungi. With rare exceptions, the paleontologists have remained as oblivious as Darwin, but the evolutionary responses to ID leave few qualitative marks on the fossil record. We can only speculate how many faunal extinctions may have stemmed from ID panzootics. We must, of course, marvel at the intricacies of the immune defensive systems that have evolved to keep pace with microbial invasion. As far as current knowledge informs us, these are remarkably uniform among vertebrates, and their main outlines were laid down 200 million years ago. However, we still have a long way to go in tracing the adaptations that may distinguish species that enable rodents and carrion eaters to pursue a lifestyle that deters humans and felines. Fifty years ago, J. B. S. HALDANE (1949) published a speculative review that is now often cited as inspiring new thinking about disease and evolution. Its original venue was a supplement to La Ricerca Scientifica, recording the papers from a “Symposium on Ecological and Genetic Factors in Speciation Among Animals.” This was organized by Adriano Buzzati-Traverso and held at the Istituto Sieroterapico Milanese. Among the few recent citations to any other papers presented there were a handful referring to Helen Spunvay and Th. Dobzhansky. But DOBZHANSKY (1951) did not refer to the Haldane paper in his Genetics and thP Origin of Species (Ed. 3). Others present at the Symposium included R. A.