1. The pathology of the experimental dermal pneumococcic infection in the rabbit is described in detail and the findings are compared with the histological alterations seen in the human pneumonic lung. There would appear to be a basic similarity of the lesions in both tissues.
2. A copious production of edema fluid is the outstanding characteristic of the early lesion. It occurs prior to any significant cellular change. In the spreading lesion an infiltration of the tissues with fluid precedes any other sign of reaction between tissue and microorganism. It seems likely that the advancing fluid carries with it the infecting organisms and inoculates all tissues which it reaches. The resulting infection seems not to take place by an active invasion of microorganisms but by a progressive inoculation from an infected fluid.