William Maddock Bayliss's therapy for wound shock.

During World War I, military surgeons discovered that patients die from wound shock because their blood pressure falls catastrophically. William Maddock Bayliss produced experimental shock by bleeding anaesthetized cats, which lowers their blood pressure. He restored pressure by infusing salt solution containing enough gum acacia to generate the colloid osmotic pressure ordinarily contributed by the plasma proteins. Ernest Henry Starling had demonstrated that as plasma flows through the capillaries the colloid osmotic pressure of its proteins retains water. From 1917 to 1919 Bayliss and Starling served on the Special Investigation Committee on Surgical Shock and Allied Conditions of the Medical Research Committee. Both gum-saline and blood transfusions were used successfully on wound-shocked soldiers, but we do not know how many were treated, and the effectiveness of whole blood in comparison with gum-saline was not ascertained. Today the colloid osmotic pressure in transfusion solutions is usually provided by dextran or human albumin. Vast quantities are used, but Bayliss's role in the development of this clever biophysical therapy has been almost forgotten.