During the past ten years much research has been done on emphysema and asthma and on the chemistry of blood and respired air, but few studies on the mechanism of bronchiolar spasm and emphysema have been published. Some of the most recent work on this subject has been based on the assumption that the time-honored teaching of the causal relation between expiratory dyspnea and emphysema and asthma is unassailable. To me it seems that the prevailing teaching on these subjects needs revision. To learn the mechanism of emphysema and asthma by way of the chemistry of the blood gases and of the respired air seems quite hopeless. When a clear understanding of the mechanism of emphysema and asthma has been attained, we shall be in a much stronger position to interpret our chemical studies of the blood gases and respired air.
The modern interpretation of bronchiolar asthma originated
HOOVER CF. TRACHEAL AND BRONCHIAL STENOSIS AS CAUSES FOR EMPHYSEMA. Arch Intern Med (Chic). 1922;29(2):143-167. doi:10.1001/archinte.1922.00110020002001