In previous experiments,1 the amount of fluid that was lost from the blood vessels in traumatized areas has been determined. The fluid that escapes from the blood vessels into an extremity as a result of severe trauma consists largely of whole blood. The composition of the fluid that escapes from or into the injured area as a result of mild trauma to an extremity, trauma to the intestines and burns of the body surface was found by Beard and one of us (A. B.)2 to be nearly identical with that of the blood plasma. These experiments were all performed on dogs anesthetized by barbital. It was believed that the loss of fluid from the blood vessels in the injured area was the chief if not the sole factor in the production of the low blood pressure. The present experiments were undertaken in order to determine the tolerance of