Swiss physician and histologist Albert von Kölliker (1817–1905) made significant contributions to the science of cellular biology during the late 19th cen tury. A longtime professor at Würzburg University in Germany, he was confounded by the mystery of how nerve endings communicate with one another. His microscope-enabled inquiries became one of the foundational moments in the discovery of mitochondrion, the parts of cells in which essential energy-releasing chemicals are produced.
Aspecialist in the structure of cells, Albert von Külliker won the prestigious Copley Medal of the Royal Society in 1897 for his contributions to the histology of the central nervous system. His support of the work of Spanish neurologist Santiago Ramón y Cajal was instrumental in building scientific consensus regarding the behavior of nerve cells. He also holds a place of distinction in the annals of medicine as one of the first people to place his hand underneath a new apparatus—the X-ray machine—created by his friend Wilhelm Röntgen.
Rudolph Albert Kölliker was born on July 6, 1817, in Zurich, Switzerland. His father Johannes Külliker, was affiliated with Tobler-Stadler, a merchants' bank in the city, and was the son of a schoolteacher. Von Külliker's mother was born Anna Füssli, and her forebears were longtime residents of Zurich. As a boy, von Külliker was close in age to his younger brother Hans Theodor, and both were avid ice skaters who enjoyed the proximity of the city's namesake lake.
After completing his education at the gymnasium in Zurich, the 19-year-old Kölliker entered the University of Zurich in 1836, intending to study medicine. He began a period of practical training at clinics attached to the universities of Bonn and Berlin during the late 1830s and early 1840s. His first degree qualification was granted by the University of Zurich in 1841, and the University of Heidelberg awarded him a medical degree a year later.
The microscope and the increasing technological advancements made by German optical-device manufacturers like Zeiss played a crucial role in Külliker's scientific research. Histology, the microscope-enabled study of cells and tissues, was emerging at the time he began his career in Zurich, and new investigative techniques—such as dousing a tissue-sample slide with specific chemicals that would permit observation of its organic and inorganic parts—enabled anatomists and newly trained histologists to propose bold new ideas related to the composition and interaction of cells in living organisms.
Like von Siebold, who was a few years' his senior, Kölliker established his reputation in the wider European scientific community as author of an authoritative textbook. His Handbuch der Gewebelehre des Menschen was first published in 1852 and released in English translation shortly thereafter as Manual of Human Histology. He also drafted what became a classic textbook for medical-school students, Lectures on Development, and was particularly adept in embryology and the differences in epithelial cells in mammals. In 1862 he traveled to London to deliver that year's Croonian lecture, named in honor of 17th-century English anatomist William Croone. Kölliker's discourse to the members of the Royal Society and the Royal College of Physicians that year explained his recent discoveries about the properties of nerve endings in the muscle tissue of frogs.
Kölliker was also fascinated by jellyfish and other invertebrates, and he puzzled over the tissue connections he observed in their unusual cell structure. Other research involved embryonic developmental stages, which he could also observe in his laboratory at the University of Würzburg. In his writings on epithelial cells, he posited that certain types of these cells evolved into specialized sensory-processing micro-organs, like the cilia found in the inner ear or the vomeronasal organ triggering the brain's response to certain smells.
In the 1870s and '80s, major advances were made by scientists in mapping out the structure of the brain and the central nervous system. What perplexed many, including Külliker, is how neurons, or basic nerve cells, were able to communicate with one another. The predominant theory held that cells of the nervous system were threaded together by some invisible connection. This so-called reticular theory had not yet been confirmed by replicable scientific experiment. Its chief proponent was Italian pathologist Camillo Golgi, and Külliker visited Golgi in Pavia in 1887 to discuss the methodology developed by the pioneering Italian physician. Golgi used silver nitrate to stain nerve-cell slides to study their properties under a microscope; the resulting appearance was dubbed “the black reaction.”
During his time at the University of Würzburg, Kölliker's fellow professors included the Dutch-German chair of the physics department, Wilhelm Röntgen, who had connections to Kölliker's hometown of Zurich. Experimenting with gases, electrical charges, and photographic apparatus at his lab, Röntgen managed to view the bones of his hand through a specially constructed device in late 1895. He realized that there was an as-yet-unknown type of strahl—German for ray—that enabled this, and he deemed it the “X” ray, with X standing for the unknown quality. Röntgen's wife Anna was the second person to place her hand in front of the new type of camera, and the sight of her skeletal hand frightened her. Röntgen first described “On a New Kind of Rays” in a paper published on December 28, 1895. Twenty-six days later, at a meeting of the Würzburg Physical Medical Society, Kölliker became the third person to be X-rayed when he placed his hand under Rüntgen's machine.
Kölliker's final years were rewarding. He was honored by the Royal Society with its annual Copley Medal in 1897 and also received the Linnean Society of London's annual medal in 1902 for his contributions to zoological science. The University of Würzburg was one of the leading centers of scientific inquiry in the German state of Bavaria, and Külliker was ennobled by decree of Prince Regent Luitpold of Bavaria, permitting him to add the “von” before his surname. Widowed in 1901 after a 53-year marriage to Maria Schwarz von Mellingen, Kölliker died at age 88 on November 2, 1905, in Würzburg.
Kölliker, Albert, Erinnerungen aus meinem Leben, Verlag von Wilhelm Engelmann, 1899.
Rapport, Richard, Nerve Endings: The Discovery of the Synapse, W.W. Norton, 2005.□