Figure 1. Dichroa febrifuga. Reproduced from Bouillat (op. cit. p. 20).

Figure 2. Price of one kilogram of quinine sulphate in France 1880–1926. Reproduced from Perrot (op. cit. p. 159).

Figure 3. Anatomical drawings of Dichroa febrifuga. Reproduced from Bouillat (op. cit. pp. 22–23).

Figure 4. Bouillat injected an extract of the leaves of Dichroa febrifuga into a dog and measured the pressure in the carotid artery after paralysing the vagal nerve with atropine. The first white cross marks the injection of 1.25 g D. febrifuga extract. The second white cross marks the injection of 3.75 g extract leading to a ‘sudden and terminal fall in the arterial pressure’ that killed the dog. The bottom trace records the time in seconds. Reproduced from Bouillat (op. cit. p. 55).

Figure 5. The site of Zhang Changshao's laboratory outside Chongqing, photographed by Joseph Needham during the Second World War. Reproduced from Needham, J. (1945) Chinese Science, Pilot Press, p. 29. Courtesy of the Needham Research Institute.