Alterations in the blood coagulation system induced by bacterial endotoxins. II. In vitro.

Bacterial endotoxins in vitro are capable of shortening the coagulation time of normal whole blood, native platelet-rich and platelet-poor plasma, and the blood of a hemophilic patient in silicone but not in glass. The point in the coagulation system at which the endotoxins act has not been found but the search has been narrowed by the demonstration that these materials act independently of leukocytes and red blood cells, and do not act as preformed thromboplastin or thrombin. The shortening of the coagulation time in vivo 4 hours after endotoxin injection is probably through a different mechanism than in vitro.