SummaryHypocirculation causes hypercoagulability with an increase of Factors V and VIII, and a diminished platelet count. In shock hypercoagulability is followed by hypocoagulability due to loss of Factors I, II, V, VIII and XIII together with thrombocytopaenia and qualitative alterations in platelet properties. This reversal is caused by disseminated intravascular coagulation consuming clotting factors and platelets-consumptive coagulopathy.Fibrin deposits occur in the peripheral vasculature of the viscera and are associated with a rising oxygen debt, and, in clinical situations, with haemorrhagic diathesis, visceral necrosis and irreversible shock. Localization of the microthrombi is under the influence of catecholamines, ACTH and aldosterone.Administration of heparin in clinical shock may prevent the development of consumptive coagulopathy, but is without effect if disseminated intravascular coagulation is already present.Anti-fibrinolytic therapy is contraindicated whereas streptokinase-induced fibrinolysis has experimental and clinical justifications.VESSEL wall and haemostasis are closely interrelated. Experimental and clinical investigations suggest that a continuous physiological turnover of clotting factors and platelets is necessary for the proper functioning of the vessel wall. Intermediary products of intravascular haemostasis such as fibrin monomer and damaged platelets influence permeability, rigidity and resistance of the capillaries. It may very well be possible that insoluble and soluble collagen stemming from the vessel wall form the connection between tissue structure and the blood flowing by the vessel wall.The central idea of 'latent coagulation' is the continuous breakdown of prothrombin to its subunits, prothrombin, auto-prothrombin C, thrombin, Factor IX and Factor VII, which again determine the global activity of haemostasis in blood. The steady turnover of clotting factors and platelets results in the actual activity of haemostasis. Under normal conditions control mechanisms prevent a manifest clotting of the blood in the circulation. These are:(1) Inhibitors like anti-thrombokinase, heparin and progressive anti-thrombin, partly released by mast cells, partly by the vessel endothelium, which interrupt momentarily excessive activation processes.(2) Fibrinolysis which links cellular (leukocytokinase) and plasma factors (anti-thrombin IIIanti-plasmin activity) to haemostasis in the peripheral circulation, and reacts in the same manner as the system of clotting factors. Under normal conditions, the activation of blood coagulation is automatically followed by the activation of fibrinolysis. (3) (1961) have demonstrated that the injection of thromboplastin into the portal vein of rats, that is ahead of the RES, has no bearing on the global activity of haemostasis, whereas the injection of the same amount of thromboplastin into the hepatic vein results in defibrination. By electronmicroscopy, Lee & McCluskey (1962) have demonstrated material in the Kupffer cells of the liver which resembles...