RENEWED interest in plasma substitutes or plasma extenders and emergency substances has been brought about by the apparently successful production and use of dextran and polyvinylpyrrolidone abroad, the favorable impression made by their trial here, as outlined in the previous communication, and most important, the definite need for supplies of this type which may be stock-piled in large quantities for indefinite periods against major disasters.
It is now well established that certain exogenous as well as endogenous macromolecular colloids are capable of increasing and maintaining blood volume by means of their osmotic pressure, hydrophilic properties and slow elimination from the vascular system. It is the purpose of this communication to evaluate the pathologic tissue changes resulting from the introduction of these colloids rather than their physiologic effects or their effectiveness in shock and dehydration. As outlined by Hueper1 and others,2 the four exogenous macromolecular substances now most available