HARRY SMITH CBE: 7 August 1921 — 10 December 2011

Harry Smith was the person who, more than any other in the latter half of the twentieth century, prompted a renaissance of interest in the pathogenesis of microbial disease. A chemist turned microbiologist, his work on Bacillus anthracis, the causative agent of anthrax, led to the discovery in the serum of infected animals of the tripartite toxin that brings about the death of the host. These studies not only identified the first bacterial toxin, inspiring parallel work in related fields, but were seminally important in two further respects: first, they showed that toxins can be complexes of multiple components that, when studied individually, are nontoxic; and, second, they emphasized that research into infectious disease pathogenesis needs to focus on the biology of infection in vivo.