Carl Wunderlich

Carl Reinhold August Wunderlich (1815-1877)

Carl Reinhold August Wunderlich (1815 – 1877) was a German physician, pioneer, and clinical academic, who is generally regarded as the father of clinical thermometry.

Born the son of a chief district physician in Germany, Wunderlich would follow his father’s footsteps in spite of his mother’s wishes for him to become a priest, and become a pioneer of exact, physiological medicine in Germany.

Due to his progressive stance, Wunderlich would meet opposition from other members in the field of medicine throughout his lifetime, even requiring the minister of education of the kingdom of Württemberg to intercede for him in 1846. He would, however, gradually cement himself to be one of the most prominent representatives of a new generation of German doctors, and receive one of the most prestigious chairs in Germany by becoming the Dean of Medicine at the University of Leipzig.

Despite his successes, Wunderlich’s life would not be without tragedy, with him losing three of his children to illnesses and himself suffering from severe pneumonia in the later stages of his life resulting in long-lasting sequelae. The death of his son who was a doctor in 1873 affected him and his recovery greatly, and Wunderlich ultimately succumbed to his illnesses in 1877. 

Wunderlich is eponymously affiliated with Wunderlich syndrome (1856) and Wunderlich law (1868).

  • Born 4 August 1815 Sulz along the Neckar, Germany
  • 1833-1837 – Studied medicine in Tübingen
  • 1842 – Started the Archiv für Physiologische Heilkunde with Wilhelm Roser and Wilhelm Greisinger
  • 1838 – Hospital assistant in Stuttgart Hospital; obtained doctorate with his work, Die Nosologie des Typhus. Eine Beleuchtung der wichtigsten Ansichten über dieselbe
  • 1843-1846 – Assistant Professor to Georg Heermann in medicine at the University of Tübingen
  • 1846-1850 – Professor of medicine at the University of Tübingen
  • 1850 – 1877 Professor of medicine at the University of Leipzig
  • 1850 – Medical Director of Jacobs Hospital in Leipzig
  • 1854 – Medical assessor of the Königl
  • 1864-1865, 1872-1873 – Dean of the Medical Faculty of the University of Leipzig
  • 1871-1872 – Director of the University of Leipzig
  • Died 25 September 1877 Leipzig, Germany, possibly of a lymphosarcoma

Medical Eponyms
Wunderlich syndrome (1856)

Spontaneous, nontraumatic renal haemorrhage confined to the subcapsular and perirenal space. Eponym derived from Wunderlich description for Apoplexie des Nierenlagers in 1856 [Wunderlich CR. Handbuch der Pathologie und Therapie. Dritter band 1856; III: 426]

Pathology of the kidney: Renal apoplexy.

  • Aetiology: being pushed, trauma, shaken, also no specific cause.
  • Anatomical appearance: more or less uncoagulated or coagulated blood in the kidney or kidney capsule.
  • Symptoms: Sudden severe pain in the renal angle, balottable mass, obtunded, Peritonitis and death. Quite frequently, only minor haemorrhages without any or only minor symptoms occur
  • Never is the diagnosis so certain, that a specific treatment can be identified

Wunderlich CR. 1856

Historical timeline

1686 – Bonet provided an early description of the perirenal haemorrhage in a child suffering from an exanthema and in whom after death he found blood had ‘poured out around the kidneys’ [1686: Vol I Section 29 Case VII: 822]

1839 – Rayer described multiple cases of perirenal hematoma and quoted Willis (1684) and Bonet (1686) as the first to have observed and defined similar cases. Rayer termed the disease, ‘apoplexie rénale‘ and wrote extensively on the subject in his chapter Hémohhagies rénales in his Traité des maladies des reins.

1856 – Wunderlich is credited as being the first to accurately describe and classify the clinical condition in his Handbuch der Pathologie und Therapie

1910 – Coenen wrote of ‘mass bleedings in the kidney bed’ and protested against the term, ‘apoplexy’ in connection with them, preferring the term ‘perirenal hemorrhage’ or Wunderlich syndrome. [Beiträge zur klinischen Chirurgie. 1910; 70: 494-508]

Wunderlich law (1868)

Propositions relative to the temperature in typhoid fever:

  1. Any disease in which the temperature reaches 40°C on the evening of the first day is not a typhoid fever.
  2. Any illness in which the temperature does not reach 39.5°C on the evening of the fourth day is not typhoid fever.
  3. In typhoid fever the maximum temperature is first shown in the evening.
  4. On the seventh day there is a drop in temperature which never goes back to normal.
  5. Defervescence is always done by lysis.
  6. …These laws are by no means absolute.

Law derived from Wunderlich chapter on the temperature variation associated with Abdominaltyphus in Das Verhalten der Eigenwärme in Krankheiten [English and French translations]

Other Contributions
Clinical Thermometry (1868)

Clinical thermometry before Wunderlich’s time had sparingly been utilized and scientifically documented. It was only Hermann Boerhaave, with his students Gerard L.B. Van Swieten, Anton De Haen, and separately George Martine,  who started to use the thermometer at the bedside in the 18th century. De Haen studied diurnal changes in normal subjects and observed changes in temperature with shivering or fever, and he noted the acceleration of the pulse when body temperature was elevated. De Haen found that temperature was a valuable indication of the progress of an illness. However, his contemporaries were unimpressed with the findings, and the thermometer would remain to be not widely used.

It was not until the late 19th century that clinical thermometry started to gain traction, and Wunderlich was not the only clinician interested. William Aitken, a Professor of Pathology at the British Army Medical School, had designed a newer style clinical thermometer in 1852 in an attempt to solve the issue regarding the thermometer’s large size. Thomas Clifford Alburt, a prominent English physician of the time, improved on Aitken’s design to create a portable, more efficient 6-inch clinical thermometer in 1866, and published a paper on the topic of medical thermometry in 1870.

However, no clinician was able to match the sheer volume of data Wunderlich had accumulated to write his opus, Das Verhalten der Eigenwärme in Krankheiten; the same paper in which his eponymous law is famously derived from. Utilizing the older style foot-long thermometer, which required 20 minutes to determine a patient’s temperature, Wunderlich obtained over a million axillary readings from 25,000 different patients, from which he established principles, such as diurnal temperature variation, effects of aging and sex on temperature, and the correlation of fever to illness severity, which are still taught and utilized by medicine to this day.

Future studies found that the numerical data Wunderlich presented was flawed. Indeed, Wunderlich stated in his work that the upper limit of normal temperature was 38°C (100.4°F); higher than what is commonly accepted today. Speculation exists that this may be due in part to a lack of computational technology access, the fact that statistical analysis was not commonly performed until the 1890s, and the possibility that the thermometer Wunderlich used may have been inaccurate or not properly calibrated.

Despite the inaccuracies, Wunderlich’s work carried the concept of clinical thermometry one step further than others before had done and placed it back to being a measure worthy of scientific scrutiny. Arguably, the greatest contribution to arise from the work is that fever would be recognized more appropriately as a clinical sign rather than a disease.

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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