A series of 13 cases of aspergillus-infection in the respiratory tract are reviewed. A case of rapid development of an intrapleural aspergillus-mycetom is presented. A complete series of chest roentgenograms and operation-photos allowed to demonstrate like with a quick-motion apparatus 3 stages of development of an intrapleural aspergillus-myceton: I. Infection through Aspergilli of a residual intrapleural cavity by the bronchial way. Pleural thickening as reaction to the irritation. II. Development of fungus-lawn and mycotic layers on the cavity-wall. III. Scaling off from the wall and moulding to the fungus-ball through movement of human body. Each of the three stages can be coordinated to a roentgenographic sign. The detection in an early stage of development makes it possible to treat the aspergillus-mycetom also by conservative methods, f. i. with a Pimafucin-Suspension (Natamycin) by aerososl.