THE annual report by the director, Sir Spencer Lister, of the South African Institute for Medical Research, Johannesburg, gives an account of the routine and research work of the Institute for the year 1933. Concentrated anti-plague serum, prepared in the Serum Department, has been tested experimentally, and has been found to have four times the protective and curative power of the unconcentrated serum, concentration being in the same ratio. Considerable difficulty has been experienced in maintaining the virulence of the plague bacillus in culture, and this difficulty has not yet been overcome. The study of pneumonia as it occurs among native miners of the Witwatersrand goldfields was continued, and the work confirms previous findings that the disease is not a pure pneumococcus pneumonia of the earlier days of the Rand, but that other organisms are associated with, or replace, the pneumococcus, namely, the streptococcus, staphylococcus and influenza bacillus. During the year, a case of human rabies due to a cat bite was observed; the incidence of human rabies infection is on the increase in South Africa, being conveyed by the cat, the tame meercat, and occasionally the dog. The observations upon dust estimation and control in the mines have been extended, and research upon several other subjects has been continued.