The end-results of acute or chronic disease of the lung may be classified into: (1) resolution to normal conditions; (2) fibrosis, and (3) necrosis. Which of these may be the end-result of any illness depends on the factors of resistance and the character of the noxa, chemical, bacterial or mechanical, that has been the causative agent in the production of the malady. Thus, come into being the three main diseases that constitute the suppurative type of pulmonary disease, namely, empyema, bronchiectasis and abscess. Acute pulmonary disease which proceeds into chronic disease may be classified into seven groups:
Group 1. Acute fulminating inflammations that may be caused by irritating gases; these rapidly fuse with later groups unless death ensues.
Group 2. Acute streptococcal bronchopneumonia, common during the epidemic of influenza.
Group 3. Less acute, but almost equally fatal, pseudolobar pneumonia, also of streptococcal or pneumostreptococcal origin.
Group 4. Pneumonia progressing to