As I have recently suggested,1 the causes of asthma are manifold and group themselves like the parts of a tree. The main trunk of the tree represents a fundamental basis which may be called the "asthmatic state" and explains why some persons have asthma and others do not. The roots of this tree represent the causes of the asthmatic state, but so far only one root—that of inheritance—can be recognized. Upward, the tree divides into two main branches—the extrinsic and the intrinsic. Both of these can be traced through numerous subdivisions. The extrinsic branch divides into pollen, animal danders, domestic and other dusts, foods and other substances, all of which are readily recognized. Twigs on these smaller branches represent, of course, the particular pollens, the different animals, the different dusts, etc. The main intrinsic branch is likewise subdivided into groups of causes, chiefly "bacterial" and "reflex," as outlined in recent
RACKEMANN FM. STUDIES IN ASTHMAII. AN ANALYSIS OF TWO HUNDRED AND THIRTEEN CASES IN WHICH THE PATIENTS WERE RELIEVED FOR MORE THAN TWO YEARS. Arch Intern Med (Chic). 1928;41(3):346–369. doi:10.1001/archinte.1928.00130150053004
Customize your JAMA Network experience by selecting one or more topics from the list below.