In 1872, physiologist Alexander Schmidt proposed that the conversion of fibrinogen into fibrin was an enzymatic process. He named the hypothetical enzyme thrombin and its precursor prothrombin. This theory helped turn blood clotting from a mysterious bodily reaction into a biochemical process that could be measured and controlled.

Schmidt's proposal of thrombin and prothrombin in 1872 provided writers with a more precise vocabulary for blood and survival. In poetry, blood transformed into a symbol of passion and sacrifice while also reflecting the modern scientific imagination and its complexities.