Wednesday, January 11, 2017

1870: Bert's experiments advance respiratory wisdom

Paul Bert (1833-1886)
"It can be said of Paul Bert as it has been of Vesalius, Harvey and Boyle, that the full significance of his work could not be fully appreciated until long after his death." (8, page v)

This was a quote from John F. Fulton, who wrote the forward to the 1843 edition of Bert's book "Barometric Pressure."

Bert's experiments would have a broad and lasting impact on surgery, aviation, mountain climbing, deep sea excursions, mining, pressure breathing machines, and even the definition of asthma.

He was born in Auxerre, France, on October 17, 1833, attended school in Paris, and received his medical degree in 1863. (2)(8, page V)

Fulton said that while in Paris he was assistant to Dr. Claude Bernard in his laboratory.  Fulton said "Bernard recognized his ingenious mind and predicted a brilliant future." (8, page VI)

Denis Jourdanet (1815-1892)
His thesis on grafting of animal tissue gained him public acclaim, and this helped him to quickly earn fame in the medical community. (2)(8, page VI)

Animal grafting, and later skin grafting, was "an operation consisting of the removal of a living part and transplanting it so that it shall continue to live on another part of the same individual or on another individual," said the authors of an 1888 biography of Dr. Bert in Popular Science Monthly.(2)(8, page V)

In 1865, the Academy of Sciences awarded him a prize in experimental physiology for his work on animal grafting and skin grafting.  This work was significant because it allowed physicians to perform plastic surgery on soldiers injured during the war of 1870.  (2)(5, page ?)(8, page V-VI)

In 1867 he was appointed to a chair in the Faculty of Sciences at Bordeaux where he taught zoology.  Then he became Bernard's successor in December of 1869 when he was named Professor of Physiology at the Faculty of Sciences in Paris. (2)(8, page VI)(13, page 599)

In 1870 Bert became interested in respiratory disorders, such as asthma, chronic bronchitis, and emphysema.  He performed experiments to learn more about these diseases, and to find methods of helping people with these diseases.   (1, page 194)(8, page VII)

In 1854 Alton Wintrich performed experiments that seemed to disprove the spasmotic theory of asthma in favor of the diaphragmatic theory of asthma.  For 16 years Wintrich gained many followers.  But Bert aimed to prove him wrong.

In 1870 he attempted, with improved methods of scientific research compared to that used by Williams and Longet, to stimulate the vagi of dogs.  As he expected, this indeed produced dyspnea.  His experiment reaffirmed for the medical community the spasmotic theory of asthma.   (10, page 10)(11, page 37)(12, pages 5-6)(13, page 16)(14, page 599)

According to W.H. Geddings in 1885, along with demonstrating that respiration could be "arrested by irritation of the pneumogastri (vagi)," it could also be arrested by irritation of the "laryngeal nerves or the Schneiderian membrane of the nose (membrane lining the maxillary sinus cavity)." (1, page 194)

In 1855, Ludwig Traube came to a similar conclusion.

Bert's experiment was important because it prevented physicians from spending what minimal time and money was dedicated to asthma form being wasted on areas that were already disproved.

Around this time, said Fulton, a friend of his, Dr. Denis Jourdanet, had just returned from an excursion to Mexico where he had spent time in the mountains at great heights and suffered mountain sickness.  The two decided that Bert should dedicate his time performing experiments on the effects of pressure on plants, animals and humans. Jourdanet was a wealthy man, and he offered to provide any funds that Bert needed. (8, page VII)

Bert's first experiment was performed on April 15, 1874.  He sent three balloon enthusiasts and equipment in a hot air balloon called Zenith.  The mission was to collect data from the the upper atmosphere.  Another goal, however, was to exceed 24,000 feet, which was the height accomplished by an English balloonist named Glaisher in 1862.

At 26,000 feet all of the men were unconscious.  Upon the Zenith's return to the earth, two of the men had perished, and the third was insensible.  Bert hypothesized the reason was due to lack of oxygen to the brain (2)(5, page 112)(8, page VII)

This was a set back for Bert in which none of the equipment, and obviously none of the men, were able to function at that height due to cold and rarified (negative pressure, suction) air.  Most of the equipment was also damaged in the efforts made to get the balloon back down to earth, so no data could have been obtained anyway.  (2)(5, page 112)(8, page VII)

While this was a set back, it did not keep him from marching forward.  Instead of using humans to perform his studies from here on out, he did them in his laboratory using small animals.  Only when perfected his experiments did he resort to using humans.  (2)(5, page 112)(8, page VII)

The first order of business for Bert was to invent a device for measuring pressure and put together compression chambers.  He used a smaller compression chamber for small animals, and a larger one for himself and his friends.  (see figures)(2)(8, page VI)

In a laboratory experiment Bert placed a sparrow in the compression chamber made of pneumatic glass bells and exposed it to low pressures.  When it started to suffer he administered oxygen, at which point the bird "at once became himself again."  Upon this success, he performed the same experiment on himself, and he observed at higher pressures that his heart would beat faster and he'd have palpitations.  At one point he wanted to write in his tablet, but could not.  When he inhaled oxygen these symptoms went away. (7)

By these experiments he concluded that the lower the atmospheric pressure (as what would occur with high altitudes) results in oxygen tensions in the air and blood too low to support life. Instead of inhaling 21% oxygen which is present in normal room air, he was inhaling a lower percentage of oxygen.  (7)

High altitudes, or high atmospheric pressures, subject humans to the risk of suffocation or asphyxia. Early symptoms are increased heart rate,weakness, malaise, nausea, and vomiting. The colder the air the earlier these symptoms appear. For instance, the symptoms appear earlier in the Alps than in the Himalaya, Bert said. (7)

The remedy here would be "the respiration of an air sufficiently rich in oxygen to maintain the tension of that gas at its normal value." (2)

In another laboratory experiment Bert placed a sparrow in the compression chamber made of pneumatic glass bells and exposed it to high pressures (compression).  He then decompressed the bird rapidly to atmospheric pressure, at which time the bird suddenly died.  Upon inspection of the body he found air bubbles in the arteries and heart.  The same effect resulted during similar experiments performed with rats and small dogs. (5, page 115)

Robert Boyl had observed bubbles in the eyes of a snake he placed in a compression tank he invented, although no further investigations were made at that time into the nature or cause of the bubbles.  Bert, however, benefited from improved laboratory equipment.  (5, page 116)

Bert concluded that higher atmospheric pressures (as what would occur as one travels deeper under water) result in increased oxygen tensions in the air and blood.  The remedy here would be avoidance of too high a pressure (such as greater than 5-6 atmospheres), and gradual decompression back to atmospheric pressure (1 atmosphere). (2)

He observed that the effects of high pressures may kill not only humans and animals, but plants too.  (2)

While the significance of this work may not have been immediately known, the value of it was immediately recognized by the scientific community.  For this work the Academy of Sciences awarded him a prize of twenty thousand francs. (2)

His experiments would have an impact in many areas of science and medicine.

His conclusions about the effects of diminished pressure resulted in equipment, such as oxygen tanks and masks that made aviation possible.  For this reason, he is often referred to as the father of aviation medicine.

Improved methods of storing and delivering oxygen was also thought to benefit people with respiratory disorders, and so research was eventually done in this regard, some of it by Bert himself.

His conclusions about the effects of increased pressure resulted in better knowledge of decompression sickness or bends.

Bends occurs when a person moves from deep water (where the pressure is higher) to the surface (where the pressure is lower) too fast.  This causes bubbles to escape into the blood and tissues, and can cause symptoms such as headache, joint pain, nose bleeding, vertigo, shortness of breath, nausea, vomiting, and sometimes death.

This is a small compression chamber made of a pneumatic glass jar.
Bert was able to use it to expose a sparrow to low pressures.
He reduced the pressure using a manometric tube,
observing at what point the bird started to suffer.
He used the India rubber bag to administer oxygen to the bird,
and "at once the bird becomes himself again," he wrote.
He concluded that at high altitudes, where the pressure was low,
: "it appears it is not the lowering of mechanical pressure
that produces the symptoms, but the low tension of oxygen
of the dilated air, which low tension prevents the oxygen from
entering the blood in sufficient quantity." (7)
So Bert became interested in helping people with breathing difficulties during the early 1870s.  He said it was already known (such as by the works of Tavarie) that compressed air (higher pressure) helped people with anemia, chronic bronchitis, and emphysematous asthma. The result was easier breathing, and a lower heart rate. (7)(8 page VII)

Improved knowledge of the effects of high pressure on the human body resulted in Bert, and various other physicians, trying to invent machines that would adjust the pressure of inspired air to relieve the feeling of air hunger. Such machines would be experimented on patients of various lung disorders, including asthma.

In fact, in his 1877 article "Atmospheric pressure and life," Bert said:
The great influence that may be exerted upon living beings by atmospheric pressure is now questioned by none, and there is even a disposition to exaggerate its importance. If the barometric column rises or falls a few millimetres, nervous people affected with the asthma perceive phenomena, whether of a beneficial or of a noxious kind, which they do not hesitate to attribute to the weight or to the lightness of the atmosphere. But if this were the only cause of their sensations, then they should experience the same symptoms whenever they subject themselves to equal variations of pressure, as in passing from the level of the sea to a point only a few feet above it, or vice versa. (7)
In his 1878 book "Barometric Pressure," he published the results of his experiments on barometric pressure. He dedicated the book to his friend, and the man who funded the project, Dr. Jourdanet.

This is a compression chamber that allowed Bert to measure
the effects of barometric pressure on himself and others.
Inside was an Indian rubber bag so he could inhale oxygen.
Access points allowed him to take blood samples
to determine changes in blood oxygen tensions.
He exposed himself to decreased pressures.  Once he
started to feel symptoms he inhaled oxygen.  He wrote:
"But all these symptoms disappeared as by enchantment
so soon as I respired some of the oxygen in the bag;
returning, however, when I again breathed the air in
the cylinder."  (7) 
There would be many devices invented, and many failed experiments, over the next hundred years, before a truly effective, and mass producible, device would be invented to truly help patient's with respiratory disorders.  Yet it was Bert's work that got it all started.

He also performed work using anesthetics such as chloroform, and to administer it he devised an apparatus that allowed the patient to inhale an ideal percentage of the compound.   (2)(3, page 427)

Along with being a successful physician and scientist, he was also a successful politician.

As Bert was performing his experiments on pressure,
he started to wonder how the world was created.
In regards to animals dying due to compression, he wrote:
"Thus it is the oxygen that is to blame.  Oxygen at too high
a tension destroys animal life.  Long I hesitated to characterize
as a poison the 'nursing father' of everything that lives, but there
was no help for it.  Oxygen, which gives us life, slays also,
when administered in too strong a dose.  I have had to study
thoroughly this paradoxal poison to determine the different
effects of varying doses, and its action upon our tissues. (7)
So after Williams, Longet and Bert all performed experiments to prove the spasmotic theory of asthma, you probably thought the subject was settled.  Well, not quite. There still remained skeptics with credible arguments against it.

J.B. Berkart, in his 1878 book "On Asthma," explained that, during his work on asthma, Bert had a difficult time getting the air passages to contract until he realized that he had been over inflating the lungs.

Berkart said it was only when he provided less inflation that he was finally able to induce the air passages to...
"contract... upon electrical irritation, applied either directly to it or to the pneumogastric nerve.  But the contractions were so feeble and slow as to induce Bert to think that they had no active share in the mechanism of respiration.  Moreover, the paralysis of the bronchial muscles, following the section of the vagus, did not appear to influence in that least the function of nutrition of the lungs.  Thus the integrity of those muscles, not being indispensable to an efficient ventilation of the lungs, it seemed not unreasonable to conclude that their spasmodic contractions could hardly have the effect generally assigned to them."  (4, page 42-43)(9,page 5)
Berkart said that Bert's experiments did not initially demonstrate contraction of the lungs because he over inflated them.

Berkart believed that Bert's experiments demonstrated proof that the air passages may constrict as Williams proved, but this did not occur in asthma because most asthmatics also present with emphysema, which is essentially over inflation of the lungs.  (4, page 103)

Berkart's theory was respected among the medical community, although it did not have a long lasting influence.

In 1886 Bert was appointed governor-general of Tonquin, and soon thereafter his health started to fail.  On a return to France during the year he gave a farewell speech at a meeting of the Academy of sciences, supposedly because he knew he was ill. He died of dysentry on November, 11, 1886. (2)

  1. Geddings, W.H., author of the chapter on "Bronchial Asthma," in the book  "A System of Practical Medicine," edited by William Pepper and Louis Star,Volume 3, 1885, Philadelphia, Lea Brothers and Co.
  2. "Sketch of Paul Bert," Popular Science Monthly," July, 1888, Volume 33, compliments of,, accessed 2/6/14
  3. Waller, A., "Meeting of the society of Anaesthetists: Dosage in Anaesthetics," The Clinical Journal, April 6, 1898, pages 426-430, volume XI, October 27- April 20, 1898, Sixth Year, Edited by L. Eliot Creasy, 1898, London, The Medical Publishing Company
  4. Berkart, J.B., "On Asthma: It's pathology and treatment," 1878, London, J. & A. Churchill
  5. Phillips, John L., "The Bends," 1998, Yale University
  6. Tissier,Paul Lewis Alexandre, edited by Solomon Solis Cohen, "Pneumotherapy: Including Aerotherapy and inhalation methods," volume X, 1903, Philadelphia, P. Blakiston's Sons and Co., pages 296-224.  If the profession of respiratory therapy existed in their era, we would be reading their books.  However, as it was, their books were written for the medical profession. All of the material from this post is from Tissier's book unless otherwise noted in the above paragraphs. Tissier page 72
  7. Bert, Paul,  "Atmospheric pressure and life," Translated from the French by J. Fitzgerald, Popular Science Monthy, July, 1877, volume 11,, accessed 2/8/14
  8. Fulton, John F., author of the Forward to Paul Bert's book "Barometric Pressure," 1843, Columbus, Ohio, The F. J. Heer Printing Company
  9. Bert, Paul,  "Barometric Pressure," 1843, Columbus, Ohio, The F. J. Heer Printing Company
  10. Dobell, Horace, "On Asthma: It's nature and treatment," 1886, London, Smith, Elder and Co
  11. Brown, Orville Harry, "Asthma, presenting an exposition of nonpassive expiration theory," 1917, St. Louis, C.V. Mosby Company
  12. Thorowgood, John Charles, "Notes on Asthma," 1878, 3rd edition, London, J and A Churchill
  13. Thowowgood, John Charles, "The Lettsomian Lectures: delivered at the Medical Society of London, 1879, on bronchial asthma: it's causes, pathology and treatment," 1879, London, Bailliere, Tindall, and Cox
  14. West, Samuel Hatch, "Diseases of the organs of respiration," volume II, 1902, London, Charles Griffin & Company, Limited 
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