A GIANT IN PHYSIOLOGY
American physiology and medicine owes much to a German pioneer and
master teacher of the subject: Carl Ludwig. Ludwig was born in 1816 in the town
of Witzenhausen, near Cassel, in the aftermath of the Napoleonic wars. He studied
medicine at the University of Marburg, obtaining his degree in 1839. During
time as a prosector in the anatomy department there he published a dissertation
on the mechanism of urine formation, foreshadowing mechanisms of diffusion and
osmosis. A few years later he was full professor of anatomy.
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| Carl Ludwig (Wikipedia) |
Ludwig’s ascent occurred during a time when German sciences were
hampered by backwardness and a lingering belief in a “vital force” to explain
phenomena in living material. Fortunately he was close to the chemist, Robert
Bunsen (of the Bunsen burner), who influenced him to think of chemistry and
physics as drivers of life processes. Shortly after, in 1847, Ludwig, an inveterate experimenter, invented
the kymograph, a revolving drum coated with soot, on which a needle recorded
events over time, such as pulse, respiration, etc. Its simplicity and its value
in visualizing these processes made it popular in physiology labs
worldwide.
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| Ludwig's Kymograph (Wikipedia) |
In that same year Ludwig traveled to Berlin where he met Hermann von
Helmholtz, Emil du Bois-Reymond, and Ernst von Brücke – all students of
Johannes Müller, one of the first physiologists. Müller’s three students and
Ludwig formed a quartet that set out to change concepts in physiology and
anchor the entire subject in chemistry, physics, and anatomy, rejecting ideas
of a “vital” force. They were largely successful.
Two years later Ludwig went to Zurich as Professor of Anatomy and
Physiology. There he devised methods to measure blood flow and blood gases and
published the first volume of a new, groundbreaking text, Lehrbuch der Physiologie (textbook of physiology). It was the first
“modern” such text and a direct refutation of the “vitalist” theories of
biology that postulated that body functions could not be explained by chemistry
and physics alone.
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| Page from Vol. 1, Lehrbuch der Physiologie (Hathi Trust) |
After a short time in Vienna (where volume two of his text was
published) Ludwig was asked to head a new physiology institute at Leipzig in
1865. This was to be the most modern in the world. It consisted three separate
wings, in the shape of an E, for anatomy (and histology), chemistry, and
(biological) physics, with a conference room in the middle. At Leipzig he made
many other discoveries and achieved great fame. Pupils came to him from around
the world. He had up to ten advanced students working on research projects at
one time, and usually allowed the students to publish under their own names
even though the ideas for the projects were usually Ludwig’s.
Subjects investigated in Ludwig’s lab included researches on blood flow
and pressure, and the nervous control of the vasculature and heart. The
vasomotor center in the medulla was discovered there. Studies of the exchange
of gases in the tissues, the origin of lymph and the dynamics of its flow,
details of fine vessel circulation in the eye, ear, intestines, and muscles,
were other subjects. His original paper on renal physiology led to studies on
osmosis and diffusion. Secretion by glandular tissue and its connections with
the nervous system were also investigated.
Perhaps most important, the students he
trained went on to found modern physiology departments in other countries. His
influence was particularly strong in the United States. Henry
Bowditch, for
example, found his way from Boston to Ludwig’s institute where he was amazed at
the advanced level of scientific investigation. Coincidentally, Charles Eliot,
himself a chemist, had become president of Harvard and was bent on improving
the sciences and encouraging research. Eliot invited Bowditch to come as
assistant professor of physiology in the medical school. Starting in an attic
with apparatus he brought from Germany Bowditch built the first physiology
department in America, and was America’s first full-time medical school
teacher. He did further work in cardiac physiology and trained many
physiologists, including Walter Cannon.
 |
| Henry P. Bowditch (Wikipedia) |
Another student of Ludwig’s was William Welch. Under Ludwig Welch
demonstrated new connections of ganglionic cells in the atrial septum. Ludwig
also steered Welch to Julius Cohnheim in Breslau for experimental work in
pathology. Cohnheim’s
recommendation helped secure Welch’s appointment to the new
Johns Hopkins Medical School, where he exerted great influence and encouraged
research.
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| William Welch (Wikipedia) |
Franklin Mall, professor of anatomy at Hopkins was another Ludwig
student. So was John Abel, professor of pharmacology at Hopkins. The list is easily expanded.
Why was Ludwig’s lab
so popular while other professors had only a couple of students? He generated
an atmosphere of enthusiasm, created by his quick mind, his clarity of
explanation of complicated subjects, the personal interest he took in every one
of his students, and the great generosity he showed in allowing his students to
publish under their own name. For Americans in particular, coming from a
country where scientific investigation was almost nonexistent, the experience
was dramatic.
Personally Ludwig was informal but
dignified, and uninterested in titles and formalities. He took great care that
the animals experimented on (and there must have been many) did not suffer, and
in fact was president of the local Society for the Prevention of Cruelty to
Animals for twenty years. Aside from science he easily conversed about art,
music, philosophy, and world politics. He was a good raconteur.
Ludwig died in 1895 at the age of 78, working up to the end. His
influence is still felt today.
SOURCES:
Frank, M H and
Weiss, J J. “The ‘Introduction’ to Carl Ludwig’s
Textbook of Human Physiology, translated by Morton H
Frank and Joyce J Weiss”. Med
Hist 1966, 10:76-86.
Cranefield, P F. “The Organic Physics of 1847 and the
Biophysics
of Today”. J Hist Med
All Sci 1957, 12: 407-23.
Fye, B. “Carl Ludwig and the Leipzig Physiological Institute:
‘a
factory of new knowledge.’” Circulation 74: 920-28.
Fye, B. “Carl Ludwig”. Clin
Cardiol 1991, 14: 361-3.
Rosen, G. “Carl Ludwig and his American Students”. Bull Hist
Med 1936, 4: 609-49.
Flexner, Simon and James. William Henry Welch and the Heroic
Age of American Medicine. 1941, Johns Hopkins Univ Press.
