Experimental arterial disease. II. The reaction of the pulmonary artery to emboli of filter paper fibers

Rabbits were injected with saline suspensions of fibers of filter paper and of mixtures of filter paper and human fibrin or filter paper and rabbit whole blood. The emboli became impacted in the pulmonary arteries or adhered to the intima. In one rabbit an embolus adhered to the endocardium of the right ventricle. An acute arteritis resulted which was finally organized leaving a diffuse or eccentric scar on the intima. The filter paper fibers were surrounded by a foreign body granuloma and localized in either the intima or adventitia. Frequently they passed entirely through the wall clausing varying amounts of injury and were found in the adventitia or perivascular lung tissue. This is interpreted as indicating the existence of a mechanism for ridding the circulation of foreign material in the blood.