Photograph of August Krogh, who showed that blood capacity for oxygen is influenced by carbon dioxide tension. Krogh was awarded the Nobel Prize in Physiology and Medicine in 1920.
Portrait of Johann Christian Reil, who emphasized irritability as a specific property of living material, and advanced the concept of the living force as a chemical factor in function. He founded the first periodical for physiology.
Photograph of Charles Robert Richet, who described anaphylaxis and indicated its functional aspects. He was given the Nobel Prize in Physiology in 1910.