The Regulation of Hemostasis: The Protein C System

Abstract
We speak very frequently of the normal clotting time. In a glass tube?... Glass tubes have held the center of the stage for quite a long time but the process of clotting is now observed in plastic vessels and a considerably longer period of time is required than when glass is used.... If the same blood were kept outside the body in a test tube made from a vein or artery it would take a very long time to clot.— Charles H. Best, 19481 EXTENSIVE investigation into the mechanisms of blood clotting has yielded substantial insights into the process . . .