Since recognition and classification of the blood groups have become general, serious posttransfusion reactions have been infrequent. However, the publication of Bordley's1 report has focused attention on a striking syndrome following transfusion with incompatible blood. He reported three such reactions and, after extensive search of the literature, fourteen adequately described additional instances. Subsequently other observers have published their experiences with this reaction.2 The clinical and pathologic similarities in all the cases reported are striking. There is sufficient evidence to indicate that the reaction is the result of hemolysis of the donor's incompatible red blood cells. A typical reaction is characterized by an immediate diminution in the output of urine (in instances of severe involvement, by complete suppression) and hemoglobinuria;3 within a few hours a moderate degree of icterus appears; the nonprotein nitrogen content of the blood rises gradually and within a few days reaches a high level,