In a previously described series of experiments,1 it was found that the introduction into the venous circulation of an embolus infected with pyogenic organisms may be followed by widely differing pathologic changes in the parenchyma of the lung (fig. 1). Around the invading embolus there may occur a local consolidation and transient pneumonitis with complete and early recovery and with no permanent pulmonary damage. Hemorrhagic infarction may occur followed either by a cicatrizing resolution or by the formation of an abscess in the infarcted area. Occasionally, there develops a massive hemorrhagic consolidation of the lobe in which the infected embolus lodges, invariably followed by death.
In attempting to explain the varying results produced by identically infected emboli, differing degrees of thrombosis within the pulmonary vessels were postulated. If thrombosis should proceed only distally from the embolus, simple infarction might be expected, whereas thrombosis both proximal and distal to the