Laennec's words are almost an echo fifty years afterward of Auenbrugger's expressions, just quoted: "I console myself," he said, "with the thought that I have accomplished a work which will earn the gratitude of all true devotees of the art of medicine, since I have succeeded in making clear many things which shed not a little light on the chapter of the obscure diseases of the chest, in which our knowledge has hitherto been so very incomplete." As a rule it may be said that medical observers whose genius leads them to step across the narrow line that separates the known from the unknown are likely to lack the appreciation of their own generation. Long before Auenbrugger or Laennec, Harvey, the discoverer of the circulation of the blood, said to friends that he did not expect any one of his generation to accept the new doctrine, and it is well known that the great medical men of the time did not accept it. Harvey is not an isolated example, and even in our own time real medical progress sometimes waits for years for recognition, while well-advertised pretended advances are occupying the centre of the stage. Auenbrugger's discovery made its impress, however, and was never entirely lost to sight. Even {74} before his death there was the consoling prospect of its meeting with adequate attention. De Haen's successor in Vienna, Maximilian Stoll, treated Auenbrugger's work very differently from his predecessors, and was the first to introduce it practically into clinical medical training. Stoll did not hesitate in his clinic, on the strength of what was discovered by means of percussion, to attempt the evacuation of fluid from the pleural cavity on a number of occasions. It can be easily understood that with their lack of knowledge of the necessity for thorough cleanliness in the surgical sense, such an operation might readily be followed by discouragingly fatal results. This actually happened in Stoll's own experience. He does not, however, seem to have abandoned his practice of tapping the chest because of this. He insisted to his students that Auenbrugger more than anyone else had experience in removing fluid, and especially purulent collections, from the chest, and he recommended the practice to them. He added that medicine owed as much to Auenbrugger for his rational method of treating effusions into the pleural cavity, whether of pus or serum, as for his diagnostic sign by which the presence of the fluid could surely be recognized. Some of Stoll's pupils took up the work of commending Auenbrugger's method, and a little book written by one of them, Eyerel, came into the hands of the distinguished French physician, Corvisart. Eyerel did not hesitate to say, in his treatise on empyema, that the practice of percussion of the thorax, a diagnostic method introduced by the very distinguished Vienna physician, Auenbrugger, had been of great help to them in the study of this disease.