An Original Letter written and Signed by Sir Joseph Barcroft to Douglas Rayner Hartree. C1920. A letter from Barcroft to Hartree about the loss of a family/friend. It mentions that everyone in the laboratory will feel the loss. The letter could be related to Hartree's 22-year-old brother Colin William dying from meningitis in February 1920 when Hartree was 23. Sir Joseph Barcroft 1872-1947 was a British physiologist best known for his studies of the oxygenation of blood. In both the First World War and Second World War he had the prestigious role of Chief Physiologist at the Gas Warfare Centre at Porton Down near Salisbury. In 1936 he was nominated, unsuccessfully, by Professor Arthur Dighton Stammers, Professor of Physiology in the University of the Witwatersrand, for the Nobel Prize in Physiology or Medicine, for his work on the respiratory function of the blood and the functions of the spleen.He was knighted in 1935. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1938. Douglas Rayner Hartree 1897-1958 was an English mathematician and physicist most famous for the development of numerical analysis and its application to the Hartree–Fock equations of atomic physics and the construction of a differential analyser using Meccano. Size is 172mm x 112mm. Condition is good. Light folding creases.