Hand-held microscope, 1930s.
© Science Museum / Science & Society Picture Library
This is the second version of a microscope developed by Dr John McArthur (1901-1996) in about 1931. This microscope is capable of demonstrating the presence of malarial parasites in the blood but is so robustly constructed as to be capable of being run over by a lorry without harm. The instrument was progresively refined and later versions were capable of phase contrast and of fluorescence microscopy.