Giulio Ceradini

Giulio Ceradini (1844 - 1894)

Giulio Ceradini (1844 – 1894) was an Italian physiologist, engineer and historical critic.

Born a twin son to an engineer, Ceradini started his career as a clinician before becoming a renowned physiologist of his time, studying under the likes of Ludwig and Helmholtz. In the later years of his life, Ceradini shifted his attention to studying the history of physiology after being denied the means to set up a physiological institute at his university. Being not averse to controversy, some of Ceradini’s historical claims were the subject of intense debate at the time.

Ceradini’s interest not only lied in the realm of physiology, but also general history and, much like that of his father and twin brother Cesare, engineering. He produced a work of award-winning engineering concerning the avoidance of railway crashes while he was still a professor of physiology, and re-discovered two globes built by the famous 16th-century geographer and cartographer Gerardus Mercator.

He is best known for his work regarding the mechanism of semilunar valve closure, and is attributed to the discovery of Bozzolo’s sign.

  • Born 17 March 1844 in Milan, Italy.
  • August 1868 – Graduated in Medicine and Surgery from the University of Palermo.
  • 1868 – Began working at Ospedale Maggiore di Milano (Policlinico of Milan).
  • 1869 – Moved to Heidelberg, Germany to be under the tutelage of Hermann von Helmholtz.
  • 1873 – Moved to Leipzig to work with Carl Frederick Wilhelm Ludwig; published his work on semilunar valves. Subsequently moved to Florenze, Italy, to research under Maurizio Schiff, and met Angelo Mosso.
  • 1873 – 1882 – Chair of physiology at the Medical School of Genoa, Italy.
  • 1881 – Conceived automatic devices for avoiding railway crashes and received a prize for his work at the First International Exhibition on Electricity in Paris, France.
  • Died July 1894 in Milan, possibly due to intestinal cancer.

Medical Eponyms
Bozzolo sign (1887)

Visible pulsation of the arteries within the nasal mucosa. Initially described with thoracic aortic aneurysm, later associated with aortic regurgitation.

Camillo Bozzolo (1845-1920) attributed his sign to the previous work and studies of Ceradini and Angelo Mosso (1846-1910)

Eclectic genius
The mechanism of semilunar valve closure

Ceradini, whilst working in the laboratory of Carl Ludwig in 1871, illustrated the mechanism of the closure of semilunar valves. He hypothesised that the closure of the heart valves was primarily as a consequence of the decelerated systolic efflux rather than static back pressure or eddies which was the current consensus

To do this, Ceradini created an experimental device to simulate heart valve closure, heart valve hemodynamics, blood flow characteristics through the valves, and most importantly the fluid dynamic processes involved in valve closure. The experiments required an excised pig’s heart and Rüdinger’s speculum cordis within the pulmonary artery and a simple tubing arrangement. A cylindrical jar, covered with an elastic rubber membrane acted as a pump to simulate systole and diastole.

Through this experiment, Ceradini demonstrated that the role of the semilunar valves was not only to decrease the diastolic reflux but to stop it completely, that the closure of the valves was not the effect of the beginning of diastole but of the end of systole, and that the elastic equilibrium position of the semilunar valves is not of closure but of semi-opening.

Valve equilibrium, incompatible in artificial (mechanical) pumps, provides the greatest contribution to the marvelous perfection of heart valves

Ceradini 1872
Physics of the railway Automatic-Block (1881)

Ceradini studied physics related to railway traffic and devised automatic devices (Block-Sistema Automatico) to avoid railway crashes. He received a prize at the First International Exhibition on Electricity (Paris 1881) for his work.

Geographical history

Ceradini discovered two globes, lying forgotten within the library of Mantua, designed by the 16th century Flemish geographer and cartographer Gerardus Mercator. Ceradini closely studied and wrote an extensive critical review on these Globi Mercatoriani.


In 1876, on his papers detailing the history of the discovery of blood circulation, Ceradini controversially attributed Matteo Realdo Colombo (1516-1599) to be one of the major discoverers of the principles of circulation. This went against the views of some such as German theologist Henri Tollin (1833-1902) and physiologist Thierry William Preyer (1841-1897), who considered Realdo Colombo to be nothing more than a plagiarizer, prompting Ceradini to defend his views. Indeed, the topic of Realdo’s contribution was a hotly debated one, with even Thomas Huxley commenting on the matter in support of Ceradini’s view, stating in a lecture delivered in 1878 at the London Free Trade Hall “… the only man who did anything which was of real importance was one Realdus Columbus.”

The 1882 discovery of the two 16th century globes in the library of Mantua was also subjected to a bit of controversy when a monk of Mantua attempted to usurp Ceradini of the credit for discovery at the time. The monk’s attempt was unsuccessful, however, and Ceradini’s subsequent critical review of the globes went on to establish itself amongst experts as a most distinguished piece of writing on historical geography.

Interesting Facts

In 1881, Ceradini was called to assist Professor Cremona in reorganizing the then neglected Vittorio Emanuele III National Library of Rome. Cremona was impressed with Ceradini’s versatility and culture during his period of assistance, to the degree that he wished to offer Ceradini a position as a librarian of the national library; a position which Ceradini showed keen interest in fulfilling. However, due to disagreements with the Minister of Education at the time, Professor Cremona no longer had the ability to appoint Ceradini of such a position, much to his dismay.

Major Publications



Eponymous terms

Lewis is an RMO at Royal Perth Hospital. He is currently interested in critical care medicine.

BA MA (Oxon) MBChB (Edin) FACEM FFSEM. Emergency physician, Sir Charles Gairdner Hospital.  Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

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