Needless to say, Laennec's sympathies were all with Corvisart. He became a favorite pupil of this great master, who did so much for scientific medicine by introducing the method of percussion, invented nearly half a century before by Auenbrugger, but forgotten and neglected, so that it [{143}] would surely have been lost but for the distinguished Frenchman's rehabilitation of its practice. Corvisart was a man of great influence. He had caught Napoleon's eye. The great Emperor of the French had the knack for choosing men worthy of the confidence he wished to place in them. His unerring judgment in this matter led him to select Corvisart as his personal physician at a moment when his selection was of the greatest service to practical medicine, for no one was doing better scientific work at the time, and this quasi-court position at once gave Corvisart's ideas a vogue they would not otherwise have had.
Corvisart's most notable characteristic was a sympathetic encouragement of the work of others, especially in what concerned actual bedside observation. Laennec was at once put in most favorable circumstances, then, for his favorite occupation of studying the actualities of disease on the living patient and at the autopsy. For nearly ten years he devoted himself almost exclusively to the care and study of hospital patients. In 1812 he was made physician to the Beaujon Hospital, Paris. Four years later he was transferred to the Necker Hospital, where he was destined to bring his great researches to a successful issue. To the Necker Hospital, before long, students from all over the world flocked to his clinical lectures, to keep themselves in touch with the great discoveries the youthful master was making. In spite of rather delicate health Laennec fulfilled his duties of physician and professor with scrupulous exactitude and with a self-sacrificing devotion that was, unfortunately, to prove detrimental to his health before very long.
One of his contemporaries says of him:
"Laennec was almost an ideal teacher. He talked very easily and his lesson was always arranged with logical method, clearness and simplicity. He disdained utterly [{144}] all the artifices of oratory. He knew, however, how to give his lectures a charm of their own. It was as if he were holding a conversation with those who heard him and they were interested every moment of the time that he talked, so full were his lectures of practical instruction."
Another of his contemporaries says, naïvely: "At the end of the lesson we did not applaud, because it was not the custom. Very few, however, who heard him once, failed to promise themselves the pleasure of assisting at others of his lectures."
The work on which Laennec's fame depended and the discovery with which his name, in the words of our great American diagnostician, Austin Flint, the elder, will live to the end of time was concerned with the practice of auscultation. This is the method of listening to the sounds produced in the chest when air is inspired and expired in health and disease, and also to the sound produced by the heart and its valves in health and disease. Nearly two centuries ago, in 1705, an old medical writer quoted by Walshe, in his "Treatise on the Disease of the Lungs and Heart" said very quaintly but very shrewdly: "Who knows but that one may discover the works performed in the several offices and shops of a man's body by the sounds they make and thereby discover what instrument or engine is out of order!"
It was just this that Laennec did. He solved the riddle of the sounds within the human workshop, to continue the quaint old figure, and pointed out which were the results of health and which of disease. Not only this, but he showed the difference between the sounds produced in health and disease by those different engines, the lungs and the heart. The way in which he was led to devote his attention originally to the subject of auscultation is described by Laennec himself with a simplicity and directness so charmingly characteristic [{145}] of the man, of his thoroughly Christian modesty, of his solicitude for even the slightest susceptibility of others and of his prompt inventive readiness, that none of his biographers has been able to resist the temptation to quote his own words with regard to the interesting incident, and so we feel that we must give them here.
He says:
"In 1816 I was consulted by a young person who was laboring under the general symptoms of a diseased heart. In her case percussion and the application of the hand (what modern doctors call palpation) were of little service because of a considerable degree of stoutness. The other method, that namely of listening to the sounds within the chest by the direct application of the ear to the chest wall, being rendered inadmissible by the age and sex of the patient, I happened to recollect a simple and well-known fact in acoustics and fancied it might be turned to some use on the present occasion. The fact I allude to is the great distinctness with which we hear the scratch of a pin at one end of a piece of wood on applying our ear to the other.
"Immediately on the occurrence of this idea I rolled a quire of paper into a kind of cylinder and applied one end of it to the region of the heart and the other to my ear. I was not a little surprised and pleased to find that I could thereby perceive the action of the heart in a manner much more clear and distinct than I had ever been able to do by the immediate application of the ear.
"From this moment I imagined that the circumstance might furnish means for enabling us to ascertain the character not only of the action of the heart, but of every species of sound produced by the motion of all the thoracic viscera, and consequently for the exploration of the respiration, the voice, the râles and perhaps even the fluctuation of fluid effused in the pleura or pericardium. With this conviction I forthwith [{146}] commenced at the Necker Hospital a series of observations from which I have been able to deduce a set of new signs of the diseases of the chest. These are for the most part certain, simple and prominent, and calculated perhaps, to render the diagnosis of the diseases of the lungs, heart and pleura as decided and circumstantial as the indications furnished to the surgeons by the finger or sound, in the complaints wherein these are of use."
This is the unassuming way in which Laennec announces his great discovery. He did not in modern fashion immediately cry "Eureka!" and announce the far-reaching importance of his method of diagnosis. For two years he devoted himself to the patient study of the application of his method and the appreciation of its possibilities and its limitations. Then he presented a simple memoir to the French Academy of Sciences on the subject. A committee of three, then distinguished members of the Academy, Doctors Portal, Pelletan and Percy were named to investigate the new discovery.