A review of the publications, dealing with the morphology of the cartilages of the tracheo-bronchial tree, shows how scarce they are and how fragmentary the contributions based on research. Isolated parts only of the bronchial tree have been investigated, mostly in single specimens or small series. Anatomical textbooks merely state that the trachea and main bronchi are supported by rings and the more distal branches by irregular, circumferentially placed plates which become smaller towards the periphery, until they disappear in the bronchioli. It is at once obvious that this old-time view is...