The obvious causal relationship of bacterial infection to inflammation has tended to obscure the broader significance of the inflammatory reaction. An immense number of sterile substances, both fluid and solid, soluble and insoluble, organic and inorganic, incite a reaction which differs in no essential respect from that which follows the invasion of micro-organisms. Even so-called physiological salt solution introduced into the body may cause acute inflammation ; absorption of a protein such as egg albumin or of a fatty substance such as sterile olive-oil is in part dependent on the same process. Views concerning the nature of inflammation are widely diverse, but all are agreed that inflammation accomplishes the destruction and solution of a variety of substances, and notably of those proteins which form the bodies of parasitic invaders. Although absorption from the tissue, so-called parenteral resorption, is made possible by processes which resemble those occurring within