therapy with 2 months of 4 drugs (rifampicin, isoniazid, pyrazinamide and ethambutol) followed by 4 months of rifampicin and isoniazid. He established specialist TB laboratories in Kenya, Uganda, Tanzania, Zambia and a central laboratory in Hong Kong. Publications He published about 250 papers dealing with (1) factors slowing the growth of tubercle bacilli that might account for the lengthy duration of treatment, including the first paper on the effects of anaerobic culture; (2) with Jean Dickinson on post-antibiotic effects to account for the success of intermittent drug dosage; (3) the curious characteristics of attenuated South Indian strains of TB; (4) the response to treatment when the strains were initially resistant to the drugs allowing identification of the action of individual drugs. Post-retirement After his notional retirement in 1985, he continued working first at the Royal Postgraduate Medical School, Hammersmith and then at St George's, University of London. He developed the technique of measuring the early bactericidal activity of drugs, which is now standard practice as the initial step in the phase II of clinical development of new drugs with Amina Jindani and colleagues in South Africa. He also introduced the concept of the 8-week phase II study with the proportion of patients obtaining negative sputum culture at 8 weeks, a standard assessment in most such studies. More recently he developed a new type of phase II 8-week study using modelling of counts of TB in sputum during treatment (with Geraint Davies and the South African MRC). He worked on several new anti-TB drugs and participated in clinical trials on high dosage rifamycins. Mitchison finally stopped regular work at the age of 95. He died in Kingston in July 2018 at the age of 98 of bilateral pulmonary embolism. References External links 1919 births 2018 deaths British microbiologists Companions of the Order of St Michael and St George Younger sons of barons People educated at Abbotsholme School People educated at The Dragon School People from Oxford