The institution of "blood banks" in many of the larger hospitals throughout the country has often made the clinician entirely dependent on stored blood for transfusion. That such blood is not equivalent to freshly drawn blood in all respects is becoming increasingly apparent. For several years it has been a routine procedure at the Hospital of the University of Pennsylvania, in the service of Dr. I. S. Ravdin, to transfuse jaundiced patients in the surgical wards both before and after operation and to combat any manifest hemorrhagic tendency with repeated transfusions. The work of Quick, 1 as well as that of Brinkhous, Smith and Warner 2 and that of Dam and Glavind, 3 has provided a rational basis for the belief that transfusion may diminish the hemorrhagic tendency in jaundice. They have shown that the hemorrhagic tendency of jaundice is associated with a prothrombin deficiency and that normal blood contains