1871: Walshe creates new asthma theory

Dr. Walshe described paralysis of the bronchial
musculature, which was essentially emphysema.
 Other physicians also observed this, one such
physician being Dr Friedrich Gustav Jakob Henle
(1809-1885).  Dr. Orville Brown said that
Henle believed  "imperfect expiration
and stenotic sounds as evidence of a paralysis
of bronchial muscles."  (2, page 33)

After Henry Hyde Salter wrote his famous asthma book "Asthma: It's Pathology and Treatment," the medical community was all but convinced as to the validity of the nervous and spasmotic theories of asthma. So when Dr. Walter Hayle Walsh came up with a third theory, he faced an uphill battle to convince the medical community, and he knew it.  

Dr. Walshe was well aware of the writings of Dr. Salter, and he supported the great asthma doctor's asthma theories.  Yet after studying the work of Rene Laennec and other physicians, he believed there was enough evidence to suggest that asthma was sometimes caused by paralysis of the bronchial musculature.  

In his book 1871 book, "A Practical Treaties on the Diseases of the Lungs," Walsh explained how he formed his theory. 

Laennec ascribed the peculiar air-distension of the lungs, found in persons asphyxiated by the mephitic gases of cesspools, to paralysis of the vagi nerves; Mr. Swan noticed similar distension in animals whose eighth pair had been divided in the neck (tide Nervous Apnosa). In both cases the contractile force of the bronchial muscles, concerned in expiration, is more or less completely annulled.  (1, pages 555)

Dr. Friedrich Gustav Jakob Henle
(1809-1885) was another physician
who supported the idea of paralysis
of bronchial muscles. He believed
 imperfect expiration and stenotic sounds
were his proof.    (2, page 33)

Vagus is Latin for wandering.  Early Roman physicians must have been amazed how this long nerve wanders throughout the body, from the brain stem all the way down to the abdomen.  In between, it branches to various viscera, or organs, including the ears, heart, lungs, diaphragm, and stomach. For this reason they referred to it as the vagus nerve.

Today it's still referred to as the vagus nerve, although it's also known as the 10th cranial nerve, the pneumogastric nerve, nerve X, or the wandering nerve.  It's responsible for many of the involuntary functions of the body, including breathing.
This refresher in mind, let's allow Walshe to continue:

If then, as we have seen, there be motive to believe that true dynamic asthma depends, as a rule, on spasmodic action of the bronchial muscular apparatus, here are speculative reasons for presuming that paralysis of the apparatus (vagus nerve) may cause an exceptional variety of the affection. Clinically, too, we meet with examples of asthma in which the comparative facility of inspiration, and difficulty of expiration, coupled with the deficiency of the usual amount of dry rhonchi (wheeze), suggest of themselves the probable existence of a minus, rather than a plus, state of power in bronchial contractility. Possibly such cases are those habitually most benefited by strychnia and galvanism. (1, pages 555-556)

Of course, upon making this observation, Walshe was aware that Dr. Salter had already succeeded in convincing the medical profession of another asthma theory. He therefore knew it would be very difficult to change the mind of a dogmatic medical profession.  He said:

This view is, however, far from being unopposed. Dr. Salter, for instance, adopting the prevailing theory that the bronchial muscles "are not, because they can not be, muscles of respiration," refuses to admit a paralytic variety of asthma. There are many clinical facts, now taking rank as accepted truths, which were once said "not to be, because they could not be," on the assumption that the conventional physiology of the hour was true. It seems to be a law of nature, that, where circular fibres embrace a tube, they are designed to influence the movement of its contents; why should the bronchial muscles have been created on a different principle? Experientia Falax! Dr. Salter may urge. True; but experimenta fallaciora.  (1, page 556)

He is not saying that all cases of asthma are paralytic in nature, just some.  As Dr. Orville Brown reminds us in his 1917 book on asthma, Walshe "adhered... to the bronchiolar muscle spasm theory to explain most cases of the disease."  (2, page 33)

So he wasn't totally opposed to the conventional wisdom regarding asthma at the time.  (16, page 33) (20, pages 13-14) (25, page 11)

References:

1. Walshe, Walter Hyde," A Practical Treaties on the Diseases of the Lungs," 1871, 4th edition, London, Smith, Elder & Company
2. Brown, Orville Harry, "Asthma, presenting an exposition of nonpassive expiration theory," 1917, St. Louis, C.V. Mosby Company
3. Thorowgood, John C., "Asthma and Chronic Bronchitis: A New Edition of Notes on Asthma and Bronchial Asthma," 1894, London, Bailliere, Tyndall, & Cox, pages 13-14)
4. Thorowgood, John C., "Asthma and Chronic Bronchitis: A New Edition of Notes on Asthma and Bronchial Asthma," 1894, London, Bailliere, Tyndall, & Cox, page 11

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1851: Bergson classifies asthma as purely nervous

Figure 2 --Bergson, among other physicians, believed signals sent
 from the brainvia the vagus to the lungs caused an asthma attack.
 You can see by this diagram that the vagus feeds the various organs
 of the body, including the heart and lungs. Vagi is singular for vagus nerve.
 The vagus is responsible for all the things your body does without
you having to think about them, such as your heart beating, your mouth
 salivating, your eyes blinking, your lungs inhaling and exhaling, etc. 

Joseph Bergson supported the nervous theory of asthma. This basically meant he also supported the spasmotic theory of asthma, considering irritation of the nerves caused asthma.

Being that asthma was purely nervous in origin, he classified it based on this theme.

So he defined two nervous types of asthma:

1. Cerebral Asthma:  The seat of disease is the brain. Signals are sent from the brain via the vagus or recurrent nerves to the respiratory organs, thus causing respiration to become impeded. (figures 1 and 2)(3, page 378)
2. Spinal Asthma: "The influence of the brain on the function of respiration remains undisturbed, but that of the spinal system is preternaturally excited, producing contractions in the bronchial tubes." (3, page 378)  He described two types of spinal asthma: 
1. Centric Spinal Asthma:  Asthma is caused by the portion of the spinal marrow that is the source of the nerves of respiration.  "Any irritation applied to it may produce asthma in its most distinct form; such as wounds, acute or chronic inflammation, effusions, pressure from tumours, and other diseases, all of which have been found connected with asthma. " (3, pages 378-379)
2. Excentric Spinal Asthma: "In this the nervous centre is free from disease, and the irritation is conveyed from without; but as this may be in three different ways, viz., in the reflex nerves or in the ganglia, or, which is the most unfrequent of all, in the motor or centrifugal nerve, we divide excentric asthma into reflex, ganglionic, and motor asthma." (3, page 379)
3. Reflex:  Asthma is caused by a reflex action
1. Cause #1:  Asthma caused by disturbance of the digestive system, such as dyspepsia (upset stomach), abuse of alcohol, intestinal worms, etc.  (3, page 379)
2. Cause #2:  Irritation of the mucous surface of the bronchial tubes. Thus asthmatic fits are often excited by breathing dust, the pollen of grass in flower (hay asthma), acrid gases, vapours of lead, powdered ipecacuanha, odour of sun-flower or hyacinths, smell of heaps of apples, vapors of chlorine, etc. (3, page 380)
3. Cause #3: Irritation of some portion of the vagus nerve itself. "When, by compression from tumours, &c., the nerve of one side is atrophied or injured, this becomes paralysed, and the nerve of the opposite side is thrown into a state of preternatural activity, and thus the phenomena of asthma ensue." In one case he described an aortic aneurism that caused atrophy of the left recurrent nerve and resulted suffocation due to croup like symptoms and edema (swelling) of the glottis. Another cause may be tumor of trachea. (3, page 380-381)



Figure 3 -- Bergson believed some forms of asthma were caused
by irritation of the recurrent nerve. You can see by this diagram that
 it branches off the vagus nerve to supply the trachea.  I would imagine
 the asthma he is referring to here is probably childhood
ailments like croup, edema of the glottis, etc.

4. Cause #4:  Influence of mental emotions, such as anger, terror, etc. A good example is fear that you are going to have an asthma attack, and you have an asthma attack. (3, page 381)  
4. Ganglionic Asthma: The diagnosis of this type of asthma is diagnosed by ruling out the others.  A ganglion is a mass of nerve cells, and Bergson believed that "sensations" from this may cause asthma. (3, page 381)(4, page 3)
5. Motor Asthma: "To this class belong all those cases in which either the muscles or the bones concerned in the motions of respiration are incapable of obeying the impulse conveyed to them from the nervous centre. Rickets, Pott's curvature, and other diseases of the bones of the thorax, are often attended with asthma." (3, pages 382-383)

So Bergson denied paralytic asthma in favor of nervous asthma, and he further came up with categories in support of his theory.

Further reading:

1. 1851: Bergson describes typical asthma attack (2/23/16)

References:

1. Berkart, J.B., "On Asthma: It's Pathology and Treatment," 1878, London, J. & A. Churchill
2. Schmiegelow, Ernest, "Asthma, considered specially in relation to nasal disease," 1890, London, H. K. Lewis; he references the following source; Bergson, Das krampf. Asthma der Erwaohsenen, Nordhausen, 1850.
3. Gill, M. H., "Review and Bibliographic Notices: "On the spasmotic asthma of adults," by Bergson, published Gill's book, "The Dublin Quarterly Journal of Medical Science," volume X, August and November, 1850, Dublin, Hodges and Smith, pages 373-388
4. Freudenthal, Wolff, "Bronchial Asthma," New York Medical Journal: A Weekly Review of Medicine, edited by Edward Swift Dunster, James Bradbridge Hunter, Frank Pierce Foster, Charles Euchariste de Medicis Sajous, Gregory Stragnell, Henry J. Klaunberg, Félix Martí-Ibáñez, volume CV, January-June, 1917 (Saturday, January 6, 1917), New York, A.R. Elliot Publishing, Co., pages 1-5
5. Brown, Orville Harry, "Asthma, presenting an exposition of nonpassive expiration theory," 1917, St. Louis, C.V. Mosby Company
6. Karl Friedrich Canstatt,  "Images from the history of medicine," nlm.nih.gov, http://ihm.nlm.nih.gov/luna/servlet/view/all/what/Portraits?os=18800&res=2&printerFriendly=1, the photo is in the public domain, accessed, 3/10/14

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1851: Reid and Bergson verify spasmotic theory of asthma

Figure 1 --

While Reid and Bergson argued that asthma was spasmotic,

Dr. Carl (Karl) Friedrich Canstatt (1807-1850), pictured here, 

was a pioneer of medicine in Germany who, in 1855,

 wrote that a differential diagnosis of asthma didn't matter 

because anti-spasmotics were equally beneficial for both diseases.

  He believed asthma was a "spasm of the breathing organs"

 as opposed to accepting the spasmotic theory of asthma. 

(1, page 32)(5, page 32)(6)

The next in a series of experiments that confirmed the spasmotic and nervous theories of asthma were performed by Dr. John Reid and Dr. Joseph Bergson. Reid performed the experiments, and later, in 1851, Bergson used these to make his argument to disprove the paralytic theory of asthma, and prove asthma was only spasmotic and nervous.

M.H. Gill, in an 1850 edition of the Dublin Quarterly Journal of Medical Science, said Bergson was a physician from Hamburg, Germany, and that he wrote a prize essay based on experiments he performed with Amedee Lefevre. (3, page 373)

Figure 2 --Bergson, among other physicians, believed signals sent
 from the brainvia the vagus to the lungs caused an asthma attack.
 You can see by this diagram that the vagus feeds the various organs
 of the body, including the heart and lungs. Vagi is singular for vagus nerve.
 The vagus is responsible for all the things your body does without
you having to think about them, such as your heart beating, your mouth
 salivating, your eyes blinking, your lungs inhaling and exhaling, etc. 

Of course at the time the two prevailing theories regarding asthma were the spasmotic and nervous theories, although another theory that was gaining steam was the paralytic theory of asthma, which basically stated that paralysis of the muscles of respiration, the muscles that make you breathe, resulted in emphysema. 

The theory, therefore, postulated that emphysema was also a part of asthma. Berkart, therefore, believed Reid's experiments proved this paralytic theory wrong.  

Of this, J.B. Berkart, in his 1878 book "On Asthma," said: 

Bergson, however, denied the existence of a paralytic asthma, because, according to the experiments of John Reid, section of both vagi (figure 2) produces no dyspnoea so long as the animals are at rest and the supply of air unlimited—a fact duly confirmed by the later experiments of Rosenthal. Bergson, therefore, admitted only the spasmodic form of the disease, consisting in paroxysmal constrictions of the bronchi and air-vesicles, in consequence of a morbid irritability of the vagus. (1, page 28)

Ernest Schmiegelow, in his 1890 book, said:

It was especially after the publication of Bergson's prize work that a decided separation was made between the idiopathic nervous asthma, characterized by its periodical attacks, which are separated by perfectly free intervals, and the numerous forms of difficulty in breathing, which appear purely symptomatic in many different complaints of the chest. To Bergson the idiopathic nervous asthma is an independent neurosis of the organs of the chest, whose origin is a cramp or spasm which like all other neuroses can be caused by a central or peripheral irritation of the nervous centre. (2, page 4)

Gill said Bergson described asthma this way:

Having detailed a number of experiments from various sources, as the result of which our author considers himself justified in the conclusion that the asthmatic fit consists in a spasmodic contraction of the bronchial and pulmonary air-cells, caused by the action of the par vagum on the muscular fibres in these structures, so that he thinks it may properly be termed spasmus bronchialis, he divides it into two kinds: the first proceeding from the brain (cerebral asthma), and the second from the spinal marrow (spinal asthma). (3, page 377) 

In other words, he believed, as with other asthma experts of his era, that asthma was both nervous and spasmotic; that irritation of the nervous center by various stimuli triggered the muscular fibers that wrap around the lungs to spasm, thus causing the various symptoms of asthma.

Further reading:

1. 1851: Bergson describes typical asthma attack (2/23/16)

References:

1. Berkart, J.B., "On Asthma: It's Pathology and Treatment," 1878, London, J. & A. Churchill
2. Schmiegelow, Ernest, "Asthma, considered specially in relation to nasal disease," 1890, London, H. K. Lewis; he references the following source; Bergson, Das krampf. Asthma der Erwaohsenen, Nordhausen, 1850.
3. Gill, M. H., "Review and Bibliographic Notices: "On the spasmotic asthma of adults," by Bergson, published Gill's book, "The Dublin Quarterly Journal of Medical Science," volume X, August and November, 1850, Dublin, Hodges and Smith, pages 373-388
4. Freudenthal, Wolff, "Bronchial Asthma," New York Medical Journal: A Weekly Review of Medicine, edited by Edward Swift Dunster, James Bradbridge Hunter, Frank Pierce Foster, Charles Euchariste de Medicis Sajous, Gregory Stragnell, Henry J. Klaunberg, Félix Martí-Ibáñez, volume CV, January-June, 1917 (Saturday, January 6, 1917), New York, A.R. Elliot Publishing, Co., pages 1-5
5. Brown, Orville Harry, "Asthma, presenting an exposition of nonpassive expiration theory," 1917, St. Louis, C.V. Mosby Company
6. Karl Friedrich Canstatt,  "Images from the history of medicine," nlm.nih.gov, http://ihm.nlm.nih.gov/luna/servlet/view/all/what/Portraits?os=18800&res=2&printerFriendly=1, the photo is in the public domain, accessed, 3/10/14

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1800-1900: Eleven asthma theories

The 19th century was an "age of enlightenment" where physicians and scientists started to question old theories of medicine and come up with new ones.  This was an important time in our history, because without it we might probably still be stuck with primitive medicine.

This era was particularly important to the evolution of asthma, as all the theories regarding it, old and new, were hotly debated.  Some physicians were dogmatic, holding on to one particular theory for dear life, while others were more open minded.  Either way, the fact that the disease was openly discussed in the arena of ideas allowed physicians to better understand this disease.

Think of it this way:

• Before 400 B.C. asthma was just another mysterious disease caused by evil spirits or gods.
• In 400 B.C. the Hippocratic writers defined asthma as dyspnea. 
• Around 1700 John Fuller defined asthma as a disease entity of its own, slightly more severe than dyspnea and less severe than orthopnea 
• During the 18th century asthma was basically believed to be a disease in some way associated with and caused by sputum.

During the course of the 19th century there were eleven theories regarding asthma that were hotly debated.  Some were ancient ideas, and some were new.  The most prevalent of these theories are listed here. 

1. Humoral theory of asthma:  This theory postulates that asthma was caused by an imbalance of the four humours: black bile, yellow bile, phlegm and blood. This was the prevailing theory from about 400 B.C. (and probably sooner) when Hippocrates defined it, and the 1st century when Galen reaffirmed it, to the 19th century when scientific theories disproved it. More specifically, Galen believed asthma was caused by an over abundance of phlegm.
2. Dyspnea theoery of asthma:  That asthma and dyspnea are the same thing was established by Hipporates.  Basicallly anything that causes you to be short of breath is asthma; asthma is a symptom, an entity, as opposed to a specific disease. This theory was on the way out the door by the turn of the 19th century, although was pretty much the prevailing thought until the 18th century when scientists and physicians realized there were various causes of dyspnea, and started treating asthma as a disease and not just a symptom.  
3. Symptomatic theory of asthma:  Many physicians believed asthma was nothing more than a symptom of some other malady, such as heart, lung or kidney disease.  Sometimes the cause remained mysterious.  
4. Bronchitic theory of asthma:   Wheezes and dyspnea depend on obstruction of the air tubes by the inflammatory products of bronchitis. This results in excessive mucus production. Dyspnea is less severe and more constant than a paroxysm of asthma. This was the prevailing theory during the 18th century, and it made its way into the 19th century through the writings of Dr. Robert Bree.  A variation of this theory held great sway at the end of the 19th century and was referred to as the Theory of vessel turgescence.  This is basically inflammation of the mucosal membranes that line the respiratory tract, and we might think of it today as bronchitis.  
5. Spasmotic/ convulsive theory of asthma:  Convulsions, Contractions or spasms of the muscles that line the bronchioles are a main component of asthma.  Celsus defined asthma as being caused by "the narrow passage by which the breath escapes, it comes out with a whistle."  The theory was introduced to the medial community by Thomas Willis in 1682, and William Cullen in the next century fine tuned it.  It was a hotly contested theory during the 19th century. 
6. Nervous theory of asthma:  The belief that asthma is nervous in origin, or caused by things that influence the mind -- such as strong emotions like laughter, crying, stress, excessive happiness, excessive sadness, a yearning for the mother, etc -- goes back to the ancient world. Physicians early on observed no organic lesions in asthmatic lungs, and therefore assumed it must be nervous in origin.  They observed asthma was intermittent, sometimes with long intermissions between paroxysms.  This theory the nerves caused spasms in the lungs was introduced to the medical community in the 16th century by Jan Baptiste van Helmont and Thomas Willis, and in the 18th century by William Cullen.  It was proven by the experiments of Francis Ramadge in 1835, Joseph Bergson and Amedee Lefevre win 1836, and Francis Romberg in 1841.  It was given true credibility by the writings of Henry Hyde Salter during the 1850s. 
7. Paralytic theory of asthma:  Asthma is caused by paralysis of the respiratory muscles and this results in dyspnea.  This idea was first established by Dr. Rene Laennec around around 1810 or 1820.  "Bronchial muscles," he said, "are paralyzed and dyspnea is expiratory, more more constant, and less spasmotic."  We might now refer to this as emphysema. (1, page 37)
8. Diaphragmatic spasm theory of asthma:  This theory postulates that tonic spasms of the diaphragm causes asthma.  This theory may have been devised by examining the way asthmatic people breath, and was probably proposed by Thomas Willis and Neumaun (?).  It was also later supported by (M. Alton) Wintrich in the mid 19th century, and later confirmed by Heinrich von Bamberger around 1870.
9. Cardiac theory of asthma:  This is the theory that asthma is caused by blood being sucked into the lungs causing congestion and dyspnea. During the 19th and early 20th centuries it was often referred to as a type of asthma.
10. Reflex theory of asthma:  This theory postulated that something other than the lungs causes it.  Eating too much or eating certain foods can effect a nerve and send a "reflex" signal to the lungs, which responds by causing the airways to contract.  For example, catarrh or inflammation of the nose can cause spasm of the muscles of the lungs by reflex action.  Most who support this theory believed some form of disturbance in the blood was the result.  Other causes of this might be a response from the urea, disturbance of metabolism, dyspepsia, etc. However, some who support this theory believed it was just an extehnsion of the nervous theory of asthma.
11. Hay fever theory of asthma:  Hay fever leads to asthma.  Some speculate inflammation (or catarrh) of the upper airway leads to inflammation of the lower airways of the lungs, leading to bronchitis or asthma. This is a theory that has recently gained momentum.
12. Other:  Yes, lots of other theories existed.  Some doctors just let their imaginations fly free. Dr. Breuer, for example, "believed there was an automatic control of breathing through the vagi and that the stretching of the alveolar walls stimulates expiration and hinders inspiration. An increasing of the total lung volume," he said, "would tend to stimulate expiration rather than inspiration." (1, page 37) Some theories may have been scientifically justified, and others, such as Breuer's, mere speculation. Other physicians noticed asthma improved after removal of polyps in the respiratory tract and sinuses.

Of all the theories regarding asthma during this era, Orville Brown said in 1917 in 1917:

The multitude of theories some ingenious and helpful and others far fetched and convincing evidence of a fruitless search, have failed to receive much attention."  (1, page 25)

For the most part, each physician had a favorite theory, found evidence to support it, and adjusted the definition slightly as evidence indicated.

So, what theory won the era? 

References:

1. Brown, Orville Harry, "Asthma, presenting an exposition of nonpassive expiration theory," 1917, St. Louis, C.V. Mosby Company.  The above mentioned theory of vessel turgescence comes from this reference also on page 25. 

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