In 1879, Kocher demonstrated experimentally that osteomyelitis is an infectious disease which is caused by a non-specific microorganism (the "micrococcus"). He showed that the infection of the bone marrow is the consequence of a hematogenous dissemination of a local infection, either cutaneous or mucous. The clinical and pathological form of the disease depends not only on the virulence of the microorganism, but also on the state of the tissue in which it develops. In the same year, Kocher suggested that acute strumitis (inflammation of the goitre) has the same aetiology; he did not, however, produce any experimental evidence for this. Thus, Kocher defined in an original way infection as the result of an interaction between a microorganism and his host