Medical Terminology Daily - Est. 2012

Medical Terminology Daily (MTD) is a blog sponsored by Clinical Anatomy Associates, Inc. as a service to the medical community. We post anatomical, medical or surgical terms, their meaning and usage, as well as biographical notes on anatomists, surgeons, and researchers through the ages. Be warned that some of the images used depict human anatomical specimens.

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A Moment in History

Jean George Bachman

Jean George Bachmann
(1877 – 1959)

French physician–physiologist whose experimental work in the early twentieth century provided the first clear functional description of a preferential interatrial conduction pathway. This structure, eponymically named “Bachmann’s bundle”, plays a central role in normal atrial activation and in the pathophysiology of interatrial block and atrial arrhythmias.

As a young man, Bachmann served as a merchant sailor, crossing the Atlantic multiple times. He emigrated to the United States in 1902 and earned his medical degree at the top of his class from Jefferson Medical College in Philadelphia in 1907. He stayed at this Medical College as a demonstrator and physiologist. In 1910, he joined Emory University in Atlanta. Between 1917 -1918 he served as a medical officer in the US Army. He retired from Emory in 1947 and continued his private medical practice until his death in 1959.

On the personal side, Bachmann was a man of many talents: a polyglot, he was fluent in German, French, Spanish and English. He was a chef in his own right and occasionally worked as a chef in international hotels. In fact, he paid his tuition at Jefferson Medical College, working both as a chef and as a language tutor.

The intrinsic cardiac conduction system was a major focus of cardiovascular research in the late nineteenth and early twentieth centuries. The atrioventricular (AV) node was discovered and described by Sunao Tawara and Karl Albert Aschoff in 1906, and the sinoatrial node by Arthur Keith and Martin Flack in 1907.

While the connections that distribute the electrical impulse from the AV node to the ventricles were known through the works of Wilhelm His Jr, in 1893 and Jan Evangelista Purkinje in 1839, the mechanism by which electrical impulses spread between the atria remained uncertain.

In 1916 Bachmann published a paper titled “The Inter-Auricular Time Interval” in the American Journal of Physiology. Bachmann measured activation times between the right and left atria and demonstrated that interruption of a distinct anterior interatrial muscular band resulted in delayed left atrial activation. He concluded that this band constituted the principal route for rapid interatrial conduction.

Subsequent anatomical and electrophysiological studies confirmed the importance of the structure described by Bachmann, which came to bear his name. Bachmann’s bundle is now recognized as a key determinant of atrial activation patterns, and its dysfunction is associated with interatrial block, atrial fibrillation, and abnormal P-wave morphology. His work remains foundational in both basic cardiac anatomy and clinical electrophysiology.

Sources and references
1. Bachmann G. “The inter-auricular time interval”. Am J Physiol. 1916;41:309–320.
2. Hurst JW. “Profiles in Cardiology: Jean George Bachmann (1877–1959)”. Clin Cardiol. 1987;10:185–187.
3. Lemery R, Guiraudon G, Veinot JP. “Anatomic description of Bachmann’s bundle and its relation to the atrial septum”. Am J Cardiol. 2003;91:148–152.
4. "Remembering the canonical discoverers of the core components of the mammalian cardiac conduction system: Keith and Flack, Aschoff and Tawara, His, and Purkinje" Icilio Cavero and Henry Holzgrefe Advances in Physiology Education 2022 46:4, 549-579.
5. Knol WG, de Vos CB, Crijns HJGM, et al. “The Bachmann bundle and interatrial conduction” Heart Rhythm. 2019;16:127–133.
6. “Iatrogenic biatrial flutter. The role of the Bachmann’s bundle” Constán E.; García F., Linde, A.. Complejo Hospitalario de Jaén, Jaén. Spain
7. Keith A, Flack M. The form and nature of the muscular connections between the primary divisions of the vertebrate heart. J Anat Physiol 41: 172–189, 1907.


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Text from the presentation at the 2014 Vesalius Continuum Meeting in Zakyhnthos, Greece by Pavlos Plessas.

Continued from: Powerful indications that Vesalius died from scurvy (1)


Original slide from the 2014 presentation
Click for a larger image


Metellus and Solenander agree on most of the details of the story, to the point that it appears the initial source of their information was the same person, however, their versions are not identical. Metellus claims to have received his information from Georgius Boucherus in person, in the presence of a reliable witness, while we do not know how many times the story was recounted before reaching Solenander. Hence, while Solenander provides some valuable information, it is Metellus’ version, notwithstanding his conjectures, that should be considered more faithful (8).

It is very clear from both versions that, some weeks into the journey, a disease broke out on board the ship. Also, more clear in Metellus than in Solenander, that Vesalius was a victim of the same disease, which was somehow connected to food and water shortages..

(Based on the above) It can be easily concluded that the mysterious outbreak does not appear to have been due to contagion on board the ship. Neither the crew was affected nor Boucherus developed symptoms, either during the voyage or in the following months, in spite of his close proximity with the patients for at least forty days. Consequently, the disease was the result of either a pathogenic factor the pilgrims came in contact with or of some nutrient deficiency.

Contact with a pathogenic factor should have happened before boarding the ship, with the possible exception of the pilgrims consuming contaminated food that was not available to the crew. That way they could have fallen ill with typhoid fever, which has a variable incubation period of up to 30 days. However, complications and death from typhoid usually occur in the third week of the illness, which would have been near the end of the journey. Vesalius would simply not have had the time to get worried, fall ill, develop complications and die by the time they reached land. His sudden collapse and death does not fit in well with typhoid either.

Original slide from the 2014 presentation
Click for a larger image

Looking for pathogenic factors on land we can distinguish between vector borne diseases and poisoning. It is, however, inconceivable that the victims of some 16th century poison would have shown no symptoms for weeks after receiving a lethal dose. Therefore, only vector born diseases need be considered and from those only the ones that are very deadly and present in the region. None of these though agree with what Metellus let us know about the disease.

When considering the various nutritional deficiencies we only need to deal with those that could have led to multiple deaths within six weeks from the onset of obvious physical symptoms, and could conceivably have appeared under the prevailing conditions of the journey and the socioeconomic and cultural traits of the region. As such, only scurvy appears to fulfil the criteria. Many may think that even scurvy is not a good candidate since a six week sailing is not thought sufficient for its appearance.

In fact, very often scurvy did not take long to appear or cause deaths. According to the naval physician Thomas Trotter it was common for an 18th century British warship of the Channel Fleet to lose up to a dozen seamen to scurvy and have another fifty hospitalised during a cruise of just eight weeks (9). A scurvy patient on a ship rarely survived for seven weeks and many died much earlier (10).

Also, it has to be pointed out that Vesalius’ journey did not last only weeks; he left Venice sometime before the 24th of May (11) and died in Zakynthos in the middle of October, a minimum of five months. More than two of these he spent sailing and the remainder in semi-desert or desert conditions. The Holy Land in Vesalius’ time was arid and mostly barren, especially in the high summer. Many pilgrims, shocked by what they saw, believed the area had been cursed by God  (12). No vegetables grew at that time of year and only some grapes, grown by Christians, and figs, growing wild, could have been ripe. Both fruit contain very little Vitamin C (13).

Article continued here: Powerful indications that Vesalius died from scurvy (3)

Sources and author's comments:
8. There are additional reasons for this. In Solenander’s version there are efforts to explain certain aspects of the story, which may have been nothing but an intermediate informant’s speculation passed on as reliable information. An example of this is that, according to Solenander, Boucherus met Vesalius and the other pilgrims in Venice, and travelled with them to Cyprus where they separated. He went to Egypt while they continued to Jerusalem. On his return journey he travelled again via Cyprus and by coincidence met the same companions on the same ship. All this is possible but unlikely, especially if he meant that the ship waited for the pilgrims for three months. There is even the suspicion that at least one part of the original story was intentionally “corrected”: Metellus says that Vesalius collapsed and died soon after disembarking, while Solenander says he died on board the anchored ship. Conventional wisdom dictates that a very sick man does not disembark and walk on the shore of Zakynthos but expires on board his ship. This is not always true but the temptation to perform a little cosmetic surgery on the story is understandable.
9. Medicina Nautica: an Essay on the Diseases of Seamen, Volume III, London 1803, p. 387.
10. James Lind, A Treatise on the Scurvy, London 1772, p. 281.
11. This is the publication date of the Examen, in the preface of which Francesco dei Franceschi recalls Vesalius’ visit to Venice.
12. Felix Faber’s description is typical: But even I said secretly in my heart: see, this is the land that is supposed to flow with milk and honey; but I see no fields for bread, no vineyards for wine, no gardens, no green meadows, no orchards, but it is all rocky, burnt by the sun and parched.
13. Figs contain about 2 mg per 100 g; grapes 3.2 mg. Data from the United States Department of Agriculture. A man whose body stores of Vitamin C are very low will need to eat 10 – 12 figs or more than 60 grapes every day just to remain above the threshold of scurvy.