it has been found that the pneumococcus primarily invades the pulmonary tissue at some point or points in the portion of the lobe proximal to the hilum , that it spreads rapidly throughout the lobe by way of the perivascular , peribronchial , and septal interstitial tissue and lymphatics , quickly reaching the pleura , and that it invades the alveolar structure primarily by way of the alveolar walls , subsequently passing into the alveolar spaces simultaneously with the outpouring of exudate into the alveoli .
C0225695
alveolar
C1515933
alveoli