McArthur revisited: fluorescence microscopes for field diagnostics.

Few scientific instruments become eponymous with their inventors. Among those that have is the 'McArthur'. As a student in the 1930s, John Norris McArthur wanted a portable microscope to take on field trips. His rugged pocket field microscope [Mcarthur, J. (1958) A new concept in microscope design for tropical medicine. Am. J. Trop. Med. Hyg. 7, 382-385] remains a classic of compact design and performance, and has been used for malaria diagnosis over several decades. The 'McArthur' has dimensions of 102x63x51mm (McArthur folded the 160mm path length with a prism) and uses phase-contrast and specialised oil immersion objective lenses. Later, a plastic version was developed and further adapted for the Open University by Kirk & Sons, UK [McArthur J. (1971) The McArthur microscope--open university model. Trans. R. Soc. Trop. Med. Hyg. 65, 438].