Christopher Johnson, British physician, 1863.
© Science Museum / Science & Society Picture Library
Carte de visite photograph of Christopher Johnson (1783-1866), 'in my eighty second year', 25 July 1863. Dr Johnson was an influential Lancaster practitioner who arranged for the chemist Edward Frankland (1825-1899) to work at Dr Lyon Playfair's London laboratory. He is shown seated, with a microscope.