1878-1885: Asthma no longer a confused term

By introducing the art of percussion to his medical practice, Jean Corvisant realized that many cases of asthma were actually diseases of other organs.  When his student, Rene Laennec, introduced percussion with auscultation to his practice, he quickly observed that asthma was truly an abused term.

These are the two 19th century asthma experts we can thank for giving us the tools necessary for differentiating asthma from other diseases and diagnosing it as a disease.  In other words, prior to the 1820s anything that caused dyspnea was regarded as asthma, and after the 1820s asthma was more carefully diagnosed.

It is by these discoveries that asthma is divided into different categories, each of which ultimately became disease entities of their own:

• Cardiac Asthma: Dyspnea due to heart disease is now heart failure 
• Kidney Asthma: Dyspnea due to kidney disease, now known as kidney failure
• Bronchitic asthma: Dyspnea due to chronically inflamed air passages and excessive sputum production, now known as chronic bronchitis

William Pepper and Louis Star published a book in 1885 called "A System of Practical Medicine.  In the opening pages they explain the following: 

Ignorant to a great extent of pathological anatomy and unprovided with the improved methods of physical diagnosis which we now possess, they (previous asthma writers) described as asthma not only the dyspnoea due to cardiac and pulmonary diseases, but also that occasioned by affections of the pleura and greater vessels. Covering such an extensive range of territory, it was found necessary to subdivide the disease into a number of varieties, each author classifying them according to his conception of the cause, seat, and nature of the trouble. Some of these—e. g. a. dyspeptic-urn—still find a place in medical literature, but the vast majority of them, having ceased to be of any practical significance, have been discarded, and are now only interesting as examples of the crude and fanciful notions which prevailed in an age during which science rather retrograded than advanced. Of the writers of this period, Willis in the seventeenth century is especially worthy of notice as being the first to describe the nervous character of asthma. Without discarding the accepted forms of the disease, he mentions another variety, characterized by spasmodic action of the muscles of the chest, to which he gave the name asthma convulsivum. The improvement in physical diagnosis resulting from the brilliant discoveries of Auenbrugger (percussion) and Laennec (stethoscope) greatly curtailed the domain of asthma with the aid of auscultation (use of stethoscope to hear lung sounds) and percussion it was discovered that most of the cases hitherto regarded as asthma were only symptoms of some organic disease.  (1, page 184)

J.B. Berkart, in his 1878 book "On Asthma: It's pathology and treatment," wrote the following:

ALL early historical traces of the affection at present called asthma are lost. Although the disease is said to be mentioned in the Bible, and described by Hippocrates, Areteaus, Galen, and Celsus, there is not the least evidence that those remarks apply to the asthma of to-day. For in the former systems of medicine, all cases presenting the same conspicuous symptoms were, regardless of their anatomical differences, considered as of a kindred nature, and grouped into classes according to imaginary types. (2, page 12)

I know these quotes are almost trivial, yet I find it interesting because these physicians, in this era, were privy to the idea that they were taking part in the rapid evolution of the definition of the disease they were studying -- asthma. Or, more accurately, they were seeing the evolution of differential diagnosis of the various disease processes that often result in dyspnea.

In essence, Laennec's discovery sparks a leap through time.  Where 7,000 years of asthma suffering resulted in little progress in the way of asthma wisdom and treatment, the next 81 years -- part of which we are now observing -- provides for asthmatics more than all those 7,000 years combined. I think that Pepper and Star and Berkart and most other authors of pulmonary diseases in this era were well aware that this was happening.

And we learn that between 1816 and 1900 many different theories about what causes asthma are created, and every one of these theories has followers.  Each expert wrote his own definition of asthma based on his beliefs about the disease, and his own experiments and observations, and his own remedies based on these beliefs."

By the various proofs, by the various debates, that transpired during the 19th century about the disease we call asthma, and of other related diseases, it resulted in a significant fine tuning the definition of asthma.  Yet in the end, the two theories that won the day were:

1. Spasmotic theory of asthma (a.k.a. bronchospasm or convulsive): There was evidence to support it
2. Nervous theory of asthma (a.k.a. it's all in your head): There was no evidence to disprove it.

Or, more commonly, that these two theories of asthma were intertwined, such that some mysterious event or object (such as a certain food, a full stomach, laughter, strong emotion, excitement, dust, or cat) excites the nervous system, which in turn sends a message to the bronchial muscles to contract.

By the end of the 19th century the ground was set for an even bigger leap through time as far as asthmatics are concerned.  By 1899 adrenaline was isolated, and this sets off a wave of wisdom that greatly improves the lives of asthmatics. Yet for the time being (no pun intended), we find ourselves drifting from cozy doctor's 

References:

1. Pepper, William,  Louis Star, "A System of Practical Medicine," Volume 3, page 184
2. Berkart, J.B., "On Asthma: It's pathology and treatment," 1878, London,  Chapter II, "History of Asthma," page 12

1854: M. Priory fine tunes stethoscope and percussion

Pierre Adolph Priory (1794-1879)

Joseph Auenbrugger, Jean Corvisart, and Rene Laennec introduced the medical community to chest percussion and auscultation.  Both techniques became valuable for helping physicians diagnose diseases of the chest, although both needed to be perfected.  

By the time of his death in 1826, Rene Laennec saw his invention of the stethoscope become accepted by his peers.  However, he would readily admit that his new tool was not yet perfected. He would spend many hours himself improving upon it, and when he died this task was left to his peers.

Pierre Adolph Piorry (often referred to as M. Priory due to his French origin) was born in 1794, served in the Napoleanic wars in Spain, and served at the Atarazanas Hospital in Spain where he was able to witness military surgery." (1, page 675)

In 1814 he returned to his medical practice in France, and, like Laennec, served as a student of Corvisart. He qualified as a physician in 1816, the same year Laennec invented his stethoscope.  (1, page 675)

This is a picture of the Priory binaural stethoscope complete with
the pleximeter(round, solid ivory disks on bottom second from left)
and fingerthimble ivory percussor (on botton right).  Picture from 1828.
Photo from http://www.antiquemed.com/binaural_stethoscope.htm

He had a gift as a teacher, and between 1817 and 1826 he delivered lectures on physiology and pathology.  In 1826 he was appointed physician to the Paris Hospital.  In 1837, after many years of attempting to do so, he became professor of medicine at Paris School of Medicine (l'Hospital de la Pitie, Paris).  He was 43.  (1, page 676)

He then took off where Laennec left off, working hard to fine tune the binaural stethoscope.  The product he ended up with would be the general design of most stethoscopes used for the rest of the 19th century.  He also worked to improve the technique of percussion.  His work in this area created excitement for the remainder of the century, although it would ultimately be for naught. (1, page 675)

A Classic Reprint Series of Priory's book
is proof his ideas are still sought after.
The first edition was published in 1826.

His stethoscope was trumpet shaped and made of wood, although it was shorter and thinner than Laennec's.  It came with a removable wood plug, ivory earpiece and chest piece, with the chest piece also serving as a pleximeter (described below).  This design was also much more pleasing to physicians, and was much easier to carry in their bags. (5)

In a 1979 Biography of Priory, Alex Sakula said of Priory:

Priory, enthused by Laennec's invention, developed an ambition to emulate the great master and to achieve fame in some similar fashion. Priory describes in his poem Dieu L'ame et Nature how he came to study percussion.  He prayed to God asking to be able to make some discovery like that of Laennec.  A few months later, he had slight pruritus and while scratching the skin over his chest he heard a sound.  He interposed a coin and scraped it and obtained a stronger sound, which varied according to the density and elasticity of the underlying organ." (1, page 577)

This is a picture of Priory's Pleximeter. (5, page 311)

Sakula said that the next day he began his work on percussion, and hoped that what Laennec had done for auscultation he could do for percussion.  On February 28, 1826, he "read a prize winning paper on his new method of percussion to the Academie Royale de Medecine.  Laennec (then very near his death) was one of those present." (1, page 577)

Scott Alison, in his 1861 book, "The physical examination of the

 chest," described the procedure of percussion as follows: 

 The pleximeter is to be placed in or over an intercostal space,

 or upon a flat surface, and fitted well with gentle pressure upon

 the body,and held by the thumb and forefinger of the left hand. 

It may be employed together with a hammer or with the fingers." 

A percussion hammer is sown here.  (5, page 311

In the paper, Sakula said, Priory described his new technique of doing percussion, which involved placing a small plate between the patient's skin and the percussing finger.  He called the plate a pleximeter from the Greek words to strike and to measure. (1, page 577)

This little gadget shows the extent that some physicians went to 

create the perfect pleximeter.  Scott Alison described it as:

"An instrument combining both a pleximeter and a hammer 

was contrived by Dr. Aldis some years ago. It consistsof a

 hammer moving on a fulcrum, and of a disc of cork which 

receives the blow of the hammer. The cork disc is placed 

upon the chest, and the hammer is raised by the finger to the

 required height. The higher the hammer is raised, the more force

 is obtained. The hammer falls by the operation of a spring.

 Great uniformity of blow is obtained by this instrument. 

This ingenious contrivance has obtained the name of 

echometer." (5, page 312)

As Laennec experimented with various materials while trying to perfect his stethoscope, Priory experimented with various materials while trying to perfect his pleximeter, said Priory, "but finally settled on a small ivory plate, 5 cm in diameter.  He also devised a combined stethoscope and pleximeter made of ivory and cedar wood." (1, page 577)

These are a few of the varieties of wooden binaural stethoscopes
in use by physicians as of 1861. (5, page 316)

After all the publicity that the stethoscope had garnished since Laennec introduced it in 1819, percussion had lost some of its luster.  Some probably believed the stethoscope would replace it completely.  (1, pages 576-577)

However, Sakula said:

"Piorry did not regard percussion as competing with auscultation, and taught that the two techniques were supplementary one to another." (1, page 577)

This is a flexible stethoscope.  In his 1861 book, Scott Alison said,
"In employing the flexible stethoscope, it is even more necessary
than in the case of the wooden instrument to observe that the object
end is well applied so as to close the tube.  If left partially open,
scarcely any sound is perceived. (5, page 321)

There were still many physicians who did not adapt his stethoscope and pleximeter.  Many who finally accepted his research on percussion came up with their own techniques for performing the procedure.  For instance, the preferred method became the use of the finger of one hand used as the pleximeter, and the finger of the other hand as the percussor.  Yet the principle is the same.  (1, page 577)

The Cyclopaedia of Practical medicine, edited in part by John Forbes, best concludes the accomplishments of Priory regarding percussion: (3, page 7)

M. Priory, a young Parisian physician, has the honor of having, if not invented, at least brought into a formal and matured shape, this new application of the discovery of Auenbrugger, and with practical results greater precision and importance than could have been anticipated. (3, page 7)

Dr. Sibson's pleximeter 

consists of a plate of 

ivory which receives

the blow, and of a brass

hammer or weight

working in a metal frame.

. The weight or hammer

is raised by the fingers;

these being removed, 

the weight or hammer 

falls upon the ivory plate

by the elasticity of an

indiarubber band connecting 

the weight or hammer 

with the ivory plate.

The hammer works

perpendicularly

to the plate. (5, page 313

Like many new tools invented or discovered to assist physicians do their jobs better, the Priory stethoscope and pleximeter were not accepted by all physicians.

Piorry remained a famous physician until his retirement at the age of 72 in 1866.  He died at age 85 in 1879.

Yet long before he passed from this world his hard work paid off.  By 1854 percussion had been fine tuned so that it was often performed not just over the chest, but over various organs of the body to help doctors diagnose any pathological disorders.

While there were various stethoscopes designed during the remainder of the 19th century after Priorry's death, most were adaptations of his design.  Examples include binaural stethoscopes made by Quain, Stokes, Arnold, Barclay, Elliotson, Dobell, Loomis, Burrow, Clark, Camman, and Furguson. (4, page 626)

These other stethoscopes were made of various materials, produced by various manufacturers, and were scattered through various publications.  Still, Priory's stethoscope remained the most popular design for the remainder of the century.

References:  

1. Sakula, Alex., "Pierre Adolphe Piorry (1794-1879): pioneer of percussion and pleximetry," October, 1979, Thorax ( 34(5): 575–581).  
2. "The Binaural Stethoscope," antiquemed.com, http://www.antiquemed.com/binaural_stethoscope.htm, information reviewed March 8, 2012
3. Forbes, John, Alexander Weedie, Conolly, editors, "The cyclopaedia of practical medicine," volume 1, London, 1833
4. Camman, Donald M, "Historical Sketch: Stethoscopes," A Reference Handbook for Medical Sciences, edited by Albert Henry Buck, by various writers, volume VI, 1888, New York, William Wood and Company, 626-628
5. Alison, Somerville Scott, "The physical examination of the chest in pulmonary consumption and its intercurrent diseases," 1861, London, John Churchill

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1808: Corvisart re-introduces chest percussion to medicine

Jean Nicolas Corvisart (1755-1821) was the
mentor and teacher of two men who would go
on to gain fame studying diseases of the chest:
 Matthew Baillie and Rene Laennec.
Another pupil of his was Marie-Francois-
Xavier Bichat, the founder of biology. 

Joseph Avenbrugger introduced the medical community to chest percussion in 1761, although his idea was flat out rejected by many and rarely used by those who learned of it.  It would be another 53 years before his idea would be accepted, and it would take the efforts of a famous physician by the name of Jean Nicolas Corvisart des Merets (1755-1821). 

J.F. Halls Dally, in a 1941 article, said Corvisart was born February 15, 1755, to Pierre Corvisart, an advocate and attorney to the Parliament of Paris. For part of his childhood he lived with an uncle who was a priest at Vimille.  He then started college at Sainte-Barbe at the age of 12, where he was a "mediocre pupil who favored of outdoor sports. (1, page 239)

Of Corvisart's childhood education, Dally said: 

He is said to have left the college almost as ignorant as when he went in, with no reputation but that of an incorrigible idler. Thus the childhood of Corvisart gave no promise of his brilliant future. (1, page 239)

Later on he started as a law student, but after spending time at medical clinics of Paris he became interested in medicine. He became particularly interested in the speeches of Dr. Anthony Petit, a professor of anatomy and medicine. It was this reason "the young Corvisart recognized the profession for which he was designed. He longed to study the animal economy, and for this purpose he determined to be a physician," said Baron Cuvier in his 1830 memoir of Corvisart. (2, page 81) (1, page 23)

Surreptitiously, as he didn't want his father to be disappointed, he attended the lectures of the most famous physicians of the day, including Petit and Pierre Joseph Desault, said Cuvier. His father ultimately found out and approved of his transfer to the medical profession. (2, page 81)

Dally said he paid his way through medical school by becoming a male nurse at at Hotel Dieu, the oldest hospital in Paris.  It was here he became greatly influenced by the surgeon Pierre Joseph Desault, chief surgeon of the Hotel Dieu. Corvisart observed diseases with him and and examined bodies.  He also delivered his own lectures on anatomy and physiology, and these were well received.  He soon became well liked by his fellow students and physicians. (1, page 239)(2, page 81)

He was offered a job as physician at Necker, although he declined this position because all who held it had to wear a particular wig that had been handed down for decades.  Other clinics had given up this tradition, but it was still alive at Necker.  When he was offered a choice of taking the job and wearing the wig, or keeping his hair, he said he'd prefer to keep his hair.  This was a minor set back, however, because other opportunities awaited him. (1, page 240)(2, page 81)

It's interesting to note that while medicine in other areas of Europe had moved forward by leaps and bounds, Cuvier said medicine in France remained much as it was in the middle ages when the Faculty of Paris was formed. He said:

Besides, there were no public lectures at the beds of the sick. In order to see a few patients, the students accompanied the elder physicians in their visits; afterwords, when these physicians were unwell, or too much busied with practice, they acted for them, and thus they continued, till at length they, too, slowly attained their professional rank. (2, page 81)

Desbois de Rochfort (1750-1786)

In 1788 he became elected as physician at Necker hospital. His predecessor was Desbois de Rochfort, (Rochfort had passed away) chief physician at Le Charite, who was the...

...real creator of clinical medicine in France.  The pupil thus succeeded the master, and the glory of the master gained added lustre. Corvisart took over the clinical teaching and from that moment his reputation, already established among his colleagues and students, began to spread outside the confines of the hospital." (1, page 240)(2, page 81)

However, unlike his predecessors, he believed it was best to diagnose diseases by their signs and symptoms and pathological anatomy, as opposed to guessing what might be found on autopsy.  (1, page 240)

Then things change for the worse in France. Although the end result would benefit the medical profession of France.  Dally said:

In 1793 the Reign of Terror began.  The medical schools were shut, anyone could call himself a doctor and treat the sick.  Medical education was three centuries behind the times. But out of the Revolution grew modern medical education.  In the new schools of Paris laboratories were instituted for scientific study; students were taught at the bedside in hospital after the manner of Sydenham.  And it was Corvisart -- formerly rejected because he wore no wig, who taught, who for he had now become the leading professor in France. He acquired the natural history of disease by collecting observations, and when possible, following the example of Morgagni, he noted from dissection and from autopsy the changes in the body that caused symptoms of disease.  His chief lectures were given at the Necker hospital, and subsequently over a term of fifteen years at Cochin Hospital." (1, page 240)

Corvisart, whose reputation increased daily, lived in close contact with the most illustrious men of the time.  In 1795, on the criterion of the first school of medicine in Paris, he was unanimously elected to fill the Chair of Clinical Medicine, for the first time included as part of public education in France. Two years later, in 1797, he was made Professor of Medicine at the College de France. (1, page 240-241) 

While Corvisart was professor of medicine at the Charite Hospital in Paris, he studied the works of Auenbrugger and found the technique of percussion useful in diagnosing his own patients.

He championed for percussion when he re-published Abenbrugger's booklet about percussion Inventum Novum in 1808.  While he didn't have to, he humbly gave credit for the discovery of percussion to Avenbrugger.

He wrote:

"I could have raised myself to the rank of an author by remodeling the work of Auenbrugger and publishing a work on percussion.  But by that I would sacrifice the name of Auenbrugger to my own vanity; that I do not wish to do: it belongs to him, it is his beautiful and rightful discovery which I wish to bring to life." (1, page 242-243)

While Corvisant supported Avenbrugger's general technique, he adjusted it slightly so that "he used the palmar surface of the extended and approximated fingers," said Alex Sakula. (6, page 576)

Corvisart used the technique to help diagnose patients with tuberculosis and other diseases of the chest.  Based on the sounds emitted he would be able to tell how large or small the tubercles inside a patient were, along with their locations. (3)

Corvisart and his students -- one of whom was Rene Laennec -- were believed to be the only physicians in the world who used percussion. Perhaps this was because Corvisart was among the few physicians who studied Auenbrugger's work.

The use of percussion was among the diagnostic techniques used by Corvisart.  He used percussion, took a pulse, listened to the patients lung sounds by placing his ear on his patient's chest, watched the patient's breathing, felt for a temperature, observed sputum and perspiration, color of the patient's skin, changes in the voice, etc.  (2, page 81)

This was the new medical diagnostic practice that had already engulfed the medical profession throughout much of Europe, all but for the exception of chest percussion and, maybe also, vocal fremitis (vibration felt by the hand on the chest when a person speaks.  Different diseases would produce different sounds, according to the Free Dictionary by Farlex).

The Catholic Encyclopedia notes that Corvisant may have been the first to describe the technique of vocal fremitis, which is where a hand is placed over the patient's chest, and the patient is asked to make a sound, such as "a" or "e."  The physician then notes the vibratjions (fremitis) felt as the person made these sounds. Corvisart found this to be another very useful procedure in diagnosing diseases of the chest.  (5)

So, in this way, Corvisart was able to add to the list of diagnostic tools used by European physicians of his era.  By using these tools, Corvisart, and based on his studies of bodies, was able to match changes on the outside of the body with changes that might be occurring inside the body.  He was, therefore, able to use observation and science to diagnose.

In this way, he was able to use observation and science to diagnose patient, as opposed to using theory and just guessing.  Perhaps it was this that most impressed the emperor of France.

Napoleon Bonaparte was a famous military leader and
emperor of France. In these days, the best,
and perhaps only, means of adapting new ideas
was to earn the respect of the ruling party.

The technique of chest percussion may not even have been adapted by the medical profession at all if not for Emperor Napolean Bonaparte (1769-1821) selecting Corvisart as his own personal physician.  (4)

Dally said Corvisart was recommended as physician to Bonaparte because he was impressed that Corvisart used a scientific technique instead of simply guessing what was wrong, as other physicians of his era did.

Some speculate it was Boneparte who convinced Corvisart to write his first book, a treaties on diseases of the heart. This work was significant to our history of asthma because it was among the essential steps needed for future physicians to pluck cardiac disorders that caused dyspnea out from under the umbrella term asthma. (1, page 243)

Of this, Dally said:

It is said that cardiology as such did not exist prior to Corvisart's work. He really created cardiac symptomatology, and established differential diagnosis between cardiac and pulmonary disease, as well as between functional and organic heart disease." (1, page 243)

Corvisart later wrote his commentaries on Auenbrugger, which was also well received by his peers. (1, page 241)(2, page 82)

Thanks to the writings of Corvisart, and later Rene Laennec, Auenbrugger's discovery would become readily accepted shortly after his death in 1807, and Auenbrugger would eventually go down as one of the great minds in medical history.

Auenbrugger did, however, live "just long enough to witness the beginning of a proper recognition of his discovery," said Dally. (1, page 243)

Of course Corvisart himself would also go down as one of the great minds in medical history, not just because he re-introduced chest percussion to medicine, but because was a great physician overall who left an indelible impression on the medical profession.

He developed apoplexy (stoke symptoms) that took away his ability to perform his job, but not his mind.  He then suffered a cardiac arrest on September 18, 1821. He left behind no family, although he left much to his family of physicians.  (2, page 82)

Further reading:

1. Laennec, the inventor of the stethoscope
2. Auenbrugger introduced chest percussion to medical profession

References:

1. Dally, J.F. Halls, "Life and times of Jean Nicolas Corvisart (1755-1821)," Proc R Soc Med., March, 1941, 34 (5), pages 239-246
2. Baron, Cuvier, "Biographical Memoir of M. Corvisart," Literary Port Folia, Thursday, March 18, 1830, No. 11, Philadelphia, pages 81-82
3. "The Catholic Encyclopedia, "Leopold Auenbrugger," http://www.newadvent.org/cathen/02072a.htm
4. Williams, Henry Smith, "The Century's Progress in Scientific Medicine," Harper's Magazine, 1899, page 3
5. "The Catholic Encyclopedia, "Leopold Auenbrugger," http://www.newadvent.org/cathen/02072a.htm
6. Sakula, Alex., "Pierre Adolphe Piorry (1794-1879): pioneer of percussion and pleximetry," October, 1979, Thorax ( 34(5): 575–581).  

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1761: Avenbrugger introduces chest percussion to medical profession

Joseph Avenbrugger (1722-1807) was not
the first physician to use chest percussion,
although he was the first to officially introduce
it to the medical profession in 1761. 

Hippocrates mentioned chest auscultation and succussion as far back as 400 B.C. thus introducing them to the medical profession. These techniques remained the only means of diagnosing diseases of the chest for greater than 2,600 years.

A new method called chest percussion was not described in 1761 by Joseph Leopold Avenbrugger, and still not generally accepted until 1807, a year before Avenbrugger's death.

Auscultation is the process of listening to sounds within the body.  To hear lung and heart sounds, the physician would place his ear upon the patient's chest, a task that was gross on large sweaty people, especially women, uncomfortable for both the physician and patient, and which may place the physician at risk of catching the victim's disease.

Succussion is the process of shaking the patient.  This was described by Hippocrates around 400 B.C. as a method of hearing puss move around in the lungs, thus allowing him to diagnose pleurisy.

Percussion is the process of tapping on a patients chest with a finger
to listen to the sounds emitted.  Physicians of today use the technique
as shown above, as it is gentler on the patient.  The presence of an
ongoing asthma attack, or air trapping, can be heard by the resonant
sound emitted.  

Percussion is the process of of gently tapping on the patient's skin to listen to the sounds emitted.  This would help the physician determine the size of an organ, and whether or not it was enlarged or diseased.

Percussion is Latin for to beat or to strike, and may have originally been used to describe the beating or striking of the first man-made instruments.  The technique may have been used as far back as the 17th century B.C. in Ancient Egypt. (1)

So while auscultation, succussion and percussion were taught in the ancient world, they were not routinely practiced until Avenbrugger learned about them by studying ancient accounts.  He then spent the next seven years silently and laboriously working on research to prove its usefulness. (1)(2, page 19)

Avenbrugger was born in Graets in Syria in 1722 to a hotel keeper who made sure his son received a good education at the University of Vienna.  At the age of 22 he became a physician at the Spanish Military Hospital where he worked for 10 years. (1)(2, page 19)

It was here he spent doing "observational and experimental studies (that) enabled him to discover that by tapping on the chest with the finger much important information with regard to diseased conditions within the chest might be obtained." (1)

In one experiment he inserted fluid into the lung of a corpse and then tapped on the chest to confirm if a dull sound was heard over the area the fluid was entered.  His studies confirmed his findings.  (1)

In other experiments he would tap on the chest to come up with a diagnosis, and when that patient died he would perform an autopsy to confirm his diagnosis.

So he learned that fluid, tumors, organs or other solid substances inside the body produced a dull sound, such as tapping over the heart or liver.  By tapping around an organ he could determine how large it was, and whether or not it was diseased.

He determined that fluid filled areas of the lungs also produced a dull sound, such as would be produced in pneumonia.  By using percussion he could not only determine that pneumonia was present, but where in the lung it was present. 

He also determined that hollow areas of the chest produced a high pitched sound, or what later physicians referred to as tympanic or resonant sound.  The removal of part of a lung would produce a high pitched sound when percussion was performed over that part of the lung. Emphysema and asthma may cause air to become trapped in the lungs, and therefore percussion of their chest will produce a high pitched sound.  So a skilled physician could diagnose asthma by percussion.

In 1761 he published his work in a 95 page booklet written in Latin called Inventum Novum ex percussione thoracis humani, ut signo abstrusos interni pectoris morbos detegendi, or "A new invention for discovering thoracic diseases by percussion of the chest."  In the book he credited his discovery to his father who would tap on kegs to determine how full they were.  (1) (2, page 19)(5, page 243)

A. Sakula, in his 1979 biography of Pierre Adolphe Piory, a man who would later help perfect the art of percussion and auscultation, quoted Avenbrugger's description of how he performed his procedure.  He described the technique of percussion as follows: (4, page 576)

"Observation 2: Of the Method of Percussion.

IV. The thorax ought to be struck, slowly and gently, with the points of the fingers brought close together and at the same time extended.

V. During percussion the shirt is to be drawn tight over the chest, or the hand of the operator covered with a glove made of unpolished leather. Scholium: If the naked chest is struck by the naked hand, the contact of the polished surfaces produces a kind of noise which alters or obscures the natural character of the sound." (4, page 576)

His booklet was translated into French, and then other languages, although, perhaps because he was a little known and modest physician, his idea was not well accepted by the medical community. (3, page 38)

Regardless, the idea of percussion was officially introduced to the medical profession, and there was just enough interest aroused by his booklet to keep his idea alive.

Avenbrugger was later described as "a simple minded, kindly and unassuming junior physician at the Vienna Hospital.  (5, page 242)

Forty-six ears after his booklet was published, a physian several years younger than him by the name of Jean Nicolas Corvisant learned about Avenbrugger's work on percussion, and he performed experiments of his own on his patients.  He learned, as did Avenbrugger, that it was very useful in diagnosing diseases of the chest.

In 1807 he republished Avenbrugger's Inventum Novum, an this time the booklet was well received, perhaps because Corvisant had a good relationship with the dictator of France, Napoleon Bonaparte.  While not obligated, he humbly and modestly gave credit for the discovery to Avenbrugger.

Yet while Corvisant helped gain fame for Avenbruger's discovery of percussion, Corvisant's former student, Rene Laennec, helped further establish the discovery in the minds of physicians, first in France, and then throughout the world, by his 1819 book Mediate Auscultation.

In this book, Laennec wrote about how great a discovery chest percussion was. He said:  (6, page 3-4)

Nay, will go so far to assert, and without fear of contradiction from those who have been long accustomed to the examination  of dead bodies, -- that before the discovery of Avenbrugger, one half of the acute cases of peripneumon and pleurisy, and almost all the chronic pleurises, were mistaken by practitioners; and that, in such instances as the superior tact of a phsician enabled him to suspect the true nature of the disease, his conviction was rarely sufficiently strong of prompt and justify the application of very powerful remedies. The percussion of the chest, according to the method of the ingenious observer just mentioned, is one of the most valuable discoveries ever made in medicine. (6, page 3-4)

So Avenbrugger lived long enough to see his discovery accepted by his peers in France in 1807.  Of this, Laennec said:

He died without  ever perhaps dreaming of the celebrity which his discovery was destined to obtain"

Avenbrugger passed away in 1808. Yet his discovery of percussion would become a common procedure performed by physicians in order to help them diagnose and treat their patients.  (6, page 19)

Further reading:

1. Laennec, history of chest percussion
2. Corvisant re-introduced chest percussion to medicine
3. Percussion and stethoscope fine tuned

References:

1. "The Catholic Encyclopedia, "Leopold Auenbrugger," http://www.newadvent.org/cathen/02072a.htm (1)
2. Andral, G., notes to the works of Rene Laennec, "A treaties on the diseases of the chest, and on mediate auscultation," translated by John Forbes, 1838, New York, Philadelphia, Samuel S. and William Wood, Thomas Cowperthwaite and Company (10
3. Williams, Henry Smith, "The Century's Progress in Scientific Medicine," Harper's Magazine, 1899, page 38
4. Sakula, Alex., "Pierre Adolphe Piorry (1794-1879): pioneer of percussion and pleximetry," October, 1979, Thorax ( 34(5): 575–581).  (11)
5. Dally, J.F. Halls, "Life and times of Jean Nicolas Corvisart" (1755-1821)," Proc R Soc Med., March, 1941, 34 (5), pages 239-246 (8)
6. Laennec, Rene Theophile Hyacinthe, "A treaties on the diseases of the chest, and on mediate auscultation," translated by John Forbes, 1838, New York, Philadelphia, Samuel S. and William Wood, Thomas Cowperthwaite and Company (9)
7. Sakula, Alex., "Pierre Adolphe Piorry (1794-1879): pioneer of percussion and pleximetry," October, 1979, Thorax ( 34(5): 575–581).  

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