With regard to cavities in the lungs, Auenbrugger was able not only to demonstrate their presence and to show by autopsy records that his localization and determination of their approximate form and size were correct, but he also understood the method of their formation and explains the reasons for certain varieties of cavities that occur. He speaks of two classes of cavity formations. From one kind there is an ichorous discharge; from the other variety the evacuations are purulent. Cavities with non-purulent secretions are situated only in the lung. Abscesses of various kinds--that is, cavities with purulent secretions--may occur in any part, or in any of the organs of the thorax. The lung cavities are usually due to the breaking down of what he calls crude tubercles. Both kinds of cavities may either be closed or have an opening into the bronchi. Auenbrugger showed very well how to distinguish, by percussion, cavities of various kinds, and set it down as a principle, that before the evacuation of the contents of the cavity percussion over it gave a distinctly dull note, resembling that obtained when the thigh is percussed, while after evacuation, as by copious expectoration, a distinctly resonant note occurred. It is clear from his discussion of the symptoms noted in cavities (at least in the opinion of Dr. Merbach, who wrote a sketch of Auenbrugger's life for the Jahresbericht der Gesellschaft für Natur und Heilkunde in Dresden, {66} in 1861), that Auenbrugger was very near the discovery of auscultation in his study of pulmonary cavities. Auenbrugger says that when a cavity has been located by means of percussion, if the hand be laid over the place beneath which it lies and the patient is asked to cough, the fremitus produced by the pus in the cavity can be felt as it moves under the coughing impulse. This is what we now know as palpation. If instead of using his hand Auenbrugger had applied his ear to the chest, auscultation would have been discovered nearly half a century before Laennec began his work upon the subject. Perhaps Merbach, who was himself a native of Styria and a professor at the University of Gratz, was for patriotic motives more ready than others might be to give Auenbrugger credit for practically discovering auscultation.