STUDIES ON INFLAMMATION : VII. FIXATION OF BACTERIA AND OF PARTICULATE MATTER AT THE SITE OF INFLAMMATION.

India ink or graphite partides injected into an area of inflammation fail to disseminate to the tributary lymph nodes. When injected into a normal peritoneal cavity they rapidly appear in the retrosternal lymph nodes. When injected into an inflamed peritoneal cavity they are fixed in situ and fail to reach the regional lymph nodes. Graphite particles injected in the circulating blood stream enter an inflamed area both as free particles owing to increased capillary permeability and also as phagocyted material within leucocytes. Bacteria (B. prodigiosus) injected into inflamed tissue are fixed at the site of inflammation and fail to disseminate to the regional lymph nodes as readily as when injected into normal tissue. Bacteria (B. prodigiosus) injected at the periphery of an inflamed area do not readily penetrate into the site of inflammation. The experiments furnish evidence, in addition to that already provided, that fixation of foreign substances by the inflammatory reaction is primarily due to mechanical obstruction caused by a fibrin network and by thrombosed lymphatics at the site of inflammation. Bacteria (B. prodigiosus and B. pyocyaneus) injected intravenously rapidly enter an inflamed area. It is suggested that localization of bacteria in a locus minoris resistentiae may be explained as the result of increased capillary permeability with subsequent accumulation and fixation of bacteria from the blood stream at the point of injury.