History of Medicine

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. 

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. 

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.  

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

Henry P. Bowditch (Wikipedia)

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.

     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

William Welch (Wikipedia)

recommendation helped secure Welch’s appointment to the new Johns Hopkins Medical School, where he exerted great influence and encouraged research.

     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.