The hemorrhagic tendency sometimes seen in patients with obstructive jaundice has been the subject of a great deal of clinical and experimental investigation since Smith1 remarked on it nearly fifty years ago. This has now culminated in discovery of the underlying deficiency and of measures by which it can promptly be corrected in most cases. In the process of the investigations many bypaths have also been explored, and while in them the ultimate cause was not found, among the accumulated data facts were encountered which contributed to the final solution of the problem. The spectacular developments of the past few years are due in part at least to such facts and to theories developed over many years as one after another of the recognized clotting elements of the blood was considered as possibly involved and then dismissed.
A deficiency of calcium was long held to be of importance,2