THE BEHAVIOUR OF INTRAVENOUSLY INJECTED PARTICLES OBSERVED IN CHAMBERS IN RABBITS' EARS

Observations have been made on non‐inflamed, inflamed and growing blood vessels in the rabbit ear chamber, following the intravenous injection of a variety of suspensions of particulate matter. The borders of the endothelial cells were not outlined by the particulate matter during several hours of observation, though a small amount adhered to the endothelium. The experiments failed to support the contention that a sticky cement substance exists between the endothelial cells of the smaller blood vessels and that this is increased during inflammation. The introduction of particulate matter into the blood stream led to the agglutination of platelets to which the particles adhered. Thrombi were thus formed which adhered to leucocytes and often entangled some erythrocytes. These thrombi formed strands which vibrated in the blood stream and fragmented forming emboli. Capillaries were frequently blocked by the thrombi. Some particulate matter was phagocytosed by leucocytes and appeared inside platelets in the blood stream and some escaped from the vessels and was later seen within macrophages, but the site and means of egress was not determined. Blood smears revealed particles inside platelets as well as those phagocytosed by leucocytes.