Jan Evangelista Purkyne, Medical Researcher, Cell Biologist (1787-1869)

1856: Jan Evangelista Purkyne

 

Jan Evangelista Purkyne (Czech: also written Johann Evangelist Purkinje) (1787-1869) was a Czech anatomist and physiologist. He was one of the best known scientists of his time. In 1839, he coined the term ?protoplasm’ for the fluid substance of a cell. His son was the painter Karel Purkyne. Such was his fame that when people from outside Europe wrote letters to him, all that they needed to put as the address was “Purkyne, Europe”. He is buried in the Czech National Cemetery in Vysehrad, Prague, modern-day Czech Republic.

 

Jan Evangelista Purkyne was born on December 17, 1787, in Libochovice, in what was then the Czech territory in the Austro-Hungarian monarchy. His father was an estate manager. After his father’s death when Jan was 6, he was encouraged to become a priest. These plans along with his own poverty led to a situation in which, from the age of 10, he was driven from one Piarist monastery school to another, learning German and Latin along the way. He was sent to the Piarist Philosophical Institute in Litomysl, and later, the Philosophical Institute in Prague. As a recent graduate of Prague’s Institute, he earned money as a tutor of rich children. In 1813, he took up medical studies at the University of Prague and in 1818, he graduated from the medical faculty. He then obtained a doctorate in 1819, following a thesis on subjective visual phenomena. By way of self-examination, he established that the visual sensations are caused by brain activity and the brain’s connection to the eye, such that they might not be triggered by external stimulation. Purkyne became a prosector, a  person with the special task of preparing a dissection for demonstration, and an assistant in the Physiology Institute at the University of Prague, but he had no opportunities to carry out his own experiments. He conducted research on vertigo phenomena, still relying on the method of self-examination in a Prague fairground on a carousel. He noticed that the vertigo direction is independent of the direction of rotation, but depends instead on the position of the head in relation to the body. Additionally, he described the phenomena of nystagmus, a vision condition in which the eyes make repetitive, uncontrolled movements, resulting in reduced vision and depth perception and can affect balance and coordination. Purkyne also analyzed the physiological phenomena that occurred after the use of certain drugs, including camphor, opium, digitalis and belladonna. He experimented on himself, sometimes going to dangerous extremes. He noticed that using one drug after another seemed to intensify the effect of the first one. He observed, nearly 30 years before Helmholtz, the interior of the eye in the light reflected into it by concave lenses. He noticed some differences of color detection in dim light, especially in comparison with the detection in daylight – what was then called the “Purkyne phenomenon“. Nowadays, it is explained by differential rod and cone excitation. He also emphasized the significance of fingerprints in crime detection, an idea that was an absolute innovation at that time.

 

Purkyne applied for a teaching position at many universities in the Austrian Empire. However, he was unsuccessful on many occasions. He was a Czech, and university officials preferred to promote German citizens to academic positions. Fortunately, his doctorate thesis was well received, and caught the attention of Goethe, who was interested in the same issue. With strong support shown by Goethe and Aleksander von Humboldt, in 1823, he was offered the position of the Professor of Physiology at the University of Breslau. His candidacy was accepted despite strong opposition from the faculty members. Thus, the most fruitful period of his career began. Purkyne’s successes in Breslau were based on excellent equipment and new techniques for the preparation of research material. He had a very modern and accurate microscope and microtome. He was the first to establish that the whole body is composed of cells. He did this 2 years ahead of T. Schwann. Paradoxically, in the history of science, Schwann is more commonly connected with this discovery. This may have resulted from the fact that Purkyne’s main interest was the inside of the cell, while Schwann described the cell membrane and was the first to use the word “cell“. Undoubtedly, Purkyne was the first to observe and account for the cell nucleus. He also noticed that cells are the structural components of animals and plants. He introduced the terms “protoplasm“ of the cells, and “plasma“ of the blood into the scientific language.

 

The modern techniques of Purkyne’s time allowed him to obtain his neurological results. In 1837, he published a paper about the ganglion cells in the brain, spinal cord, and cerebellum. He was the first to notice the significance of the grey substance of the brain. Before his discovery, scientists thought that only the white substance and nerves had any meaning. He emphasized that those cells are the centers of neurological function and that nerve fibers are like wires that transmit power from the nerves to the whole body. He accurately described the cells in the middle layer of the cerebellum with dendrites branching like a tree. They were then called Purkyne cells. Purkyne’s discoveries were often published in the dissertations of his assistants. He supervised the doctorate of David Rosenthal (1821-1875); they jointly discovered that nerves have fibers inside, and analyzed the number of nerve fibers in spinal and cranial nerves. Purkyne also established that sleep is caused by a decrease of external impulses. He conducted research on the effects of partial destruction of the animal brain by needles, being one of the earliest researchers to use this method. For many years, Purkyne used a special rotating chair and recorded all the optical, motion-associated, and physiological signs accompanying vertigo. He carried out studies in which he directed the galvanic current flow through his own skull, and observed the resulting vertigo and physiological phenomena. He determined the movement of cilia in the genital and respiratory systems, and ultimately, in the ventricles of the brain as well. In 1839, Purkyne discovered the fibrous tissue that transmits electrical impulses from the atrioventricular node to the ventricles of the heart. Today, they are called the Purkyne fibers.

 

In 1839, Purkyne opened the Physiological Institute in Wroclaw, which was the first such institute in the world. He became the dean of the medical faculty, elected to this position four times in a row. In 1850, he became a professor of physiology at the University of Prague. There, he concentrated on encouraging a return to the use of the Czech language instead of German in the university’s operations. He discovered the Purkinje effect, the human eye’s much reduced sensitivity. to dim red light compared to dim blue light. He published two volumes, Observations and Experiments Investigating the Physiology of Senses and New Subjective Reports about Vision, which contributed to the emergence of the science of experimental psychology. He created the world’s first Department of Physiology at the University of Breslau in Prussia (now Wroclaw, Poland) in 1839 and the world’s first official physiology laboratory in 1842. Here he was a founder of the Literary-Slav Society.

 

Personal Sigil 1837

 

Purkinje effect: simulated appearance of a red geranium and foliage in normal bright-light (photopic) vision, dusk (mesopic) vision, and night (scotopic) vision

 

Purkinje is best known for his 1837 discovery of Purkinje cells, large neurons with many branching dendrites found in the cerebellum. He is also known for his discovery in 1839 of Purkinje fibers, the fibrous tissue that conducts electrical impulses from the atrioventricular node to all parts of the ventricles of the heart. Other discoveries include Purkinje images, reflections of objects from structures of the eye, and the Purkinje shift, the change in the brightness of red and blue colors as light intensity decreases gradually at dusk. Purkyne was the first to use a microtome to make wafer thin slices of tissue for microscopic examination and was among the first to use an improved version of the compound microscope. He described the effects of camphor, opium, belladonna and turpentine on humans in 1829. He also experimented with nutmeg that same year, when he “washed down three ground nutmegs with a glass of wine and experienced headaches, nausea, euphoria, and hallucinations that lasted several days”, which remain a good description of today’s average nutmeg binge. Purkyne also discovered sweat glands in 1833 and published a thesis that recognized 9 principal configuration groups of fingerprints in 1823. Purkyne was also the first to describe and illustrate in 1838 the intracytoplasmic pigment neuromelanin in the substantia nigra. Purkyne also recognized the importance of the work of Eadweard Muybridge and constructed his own version of a stroboscope which he called forolyt. He put nine photos of him shot from various sides to the disc and entertained his grandchildren by showing them how he, an old and famous professor, is turning around at great speed.

 

In 1827, Purkyne married Julie Rudolphi, the daughter of a professor of physiology from Berlin. They had four children, two of whom were girls that died in early childhood. After 7 years of marriage, Julie died, leaving Purkyne with two young sons and in deep despair. Purkyne died on July 28, 1869, in Prague. He was buried in the cemetery for distinguished citizens near the Czech Royal Castle on Wyszehrad. Czechoslovakia issued two stamps in 1937 to commemorate the 150th anniversary of the birth of Purkinje (spelt Purkyne in Czech). The Masaryk University in Brno, Czech Republic, bore his name from 1960 to 1990, as did the standalone military medical academy in Hradec Kralove (1994-2004.) Today, a university in Ust? nad Labem bears his name: Jan Evangelista Purkyne University in Ust? nad Labem (Univerzita Jana Evangelisty Purkyne v Usti nad Labem.)

 

The crater Purkyne on the Moon is named after him, as is the asteroid 3701 Purkyne.

 

Sources: nih.gov; Wikipedia

 

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