I suspect that in many of our minds “the literature” begins at about the time we entered medical school. This may, of course, mean that much useful research is ignored. A fascinating example of the value of knowing about findings from a previous era has been provided by work on the location of latent tubercle bacilli (R Hernández-Pando and colleagues.Lancet2000;356:2133–8).  In 1927, E L Opie and J …