Blood and respiration.

Sir Joseph Barcroft (1872-1947) is famous for his research into the effect that altitude has on blood. In the early part of the century he travelled to the mountains of Peru and Tenerife where he studied this subject in depth, providing the basis for his textbook, The Respiratory Function of the Blood (1914). This film shows his classic experiment to demonstrate the Dissociation Curve of the Haemoglobin Oxygen System. The film was discovered in the 1970s, though was made in the 1930s. The original film is silent, but a commentary by Joseph Barcroft's son, Henry, has been added to interpret the experiments that are shown.