“…Bedell [1962], Williams [1959], as well as our own investigations [Daum, 1966[Daum, , 1969 demonstrated that the total diffusion capacity is diminished in patients with chronic bronchitis, obstructive emphysema and cor pulmonale. A further analysis revealed that the 0 2-transport in the blood component is lower in these patients as a consequence of the shrinkage of the alveolo-capillary surface due to a functional or anatom ical elimination of a given number of capillaries.…”