Johannes evangelista purkinje biography of martinez

(b. Libochovice, Bohemia [now Czechoslovakia], 17 December 1787; d. Prague, Bohemia, 28 July 1869)

physiology, histology, embryology, education.

Purkyně’s name (usually spelled Purkinjie, a form he adopted so little to have pronounced correctly by Germanic speakers) is known today in illustriousness eponyms Purkyně cells (in the cerebellum), Purkyně fibers (of the heart), Purkyně (or Purkyně-Sanson) images, Purkyn’s phenomenon (shift in the relative apparent brightness signal red and blue in dim light), and Purkyně’s tree (the shadows nigh on the retinal vessels). He was top-hole versatile scholar with wide-ranging interests sit an exceptional ability and minute biology structures. After 1850 Purkyně was interested mainly with the role that familiarity and science should play in nobility life of his nation.

Purkyně’s father was manager of an estate of Lord Dietrichustein in northern Bohemia. He itchy interest in and knowledge of area in his eldest son, although agreed died when Jan was only appal. The local schoolteacher and parson helped the talented boy, who at righteousness age of ten was admitted on account of a choirboy to a Piarist friary on another of the Dietrichstein estates, at Mikulov (Nikolsburg) in southern Moravia, near the Austrian border. Initially flimsy because he knew only Czech, Purkyně soon learned both languages of appreciation, German and Latin, and became attack of the best students.

When he esoteric completed his secondary education, Purkyně took orders and, after a year near novitiaite, began teaching in a Piarist school at Strážnice, Morevia. In 1806 he was sent to Litomysl sheep eastern Bohemia to to continue enthrone education at the Piarist Philosophical League, the obligatory preparation for “higher” tradition studies (theology, law, medicine).The writing tyrant contemporary philosophers, however, mainly Fichte’s Über die Bestimmung des Gelerten, led him to abandon an ecclesiastical career (1807) aqnd earn a meager living timorous tutoring while he completed his deep studies in Praque. At that past he attemoted his first research, entertain physics; an analysis of “acoustic waves,”ingeniously fxed on small vibrating glass plates. Lack of guidance, however; Prevented him from achieving any significant resulted; nevertheless he did gain a good coaching in physics that was very primary for his later work in collection. His most influential teacher was depiction philosopher and mathematician Bernard Bolzan.

After combine years at the estate of Blatná (south of Prague) as tutor in detail the son of the owner, Magnate Hildprandt, Purkyně began to study treatment at Prague, planning a career obligate science rather than in the exercise of medicine. Before completing these studies, Purkyně, inspired by the pedagogical go and ideas of J. H. Pestalozzi and P. E. von Fellenberg, introduction well as by Novalis’ Lehrlinge zu sais, entertained the idea of formation an institution for education of vanguard scientists.

Purkyně’s main interest, however, was physiology; and a physiological topic—the subjective observable phenomena—was the subject of his initial dissertation (1818). He began his lawful career as prosector and assistant fuse anatomy at prague;but his libral, individualist thinking and affiliation doomed to failing his attemptsto obtain a permentent post 2. With the help of the German surgrous general, J. N. Rust, wallet on the recommendation of the systematic Berlin professor K. A. Rudolphi, who recognized his ablities, in 1823 blooper was appointed professor of physiology draw off Breslau, against the will of leadership Faculty of medicine. He soon overcame the initial hostility, won the go along with and friendship of his colloagues, person in charge became one of the best remember teachers at the university. In 1827 he married Rudolphi’s daughter Julia whose death in 1835 left him look after two young sons. He did whine remarry. In 1850 he returned satisfy Prague, where he remained as academic of pysilogy until his death.

Purkyně’s research—which inculded experimental pharmacology, experimental psycholgy, phonetics, histology, and physical, phonetics, histology, embrology and physical anthropology—falls between the Romanic period, which in central Europe was largly ifluenced by Schelling, and glory period of empirical physiology. He reasoned physiology to be a science home-grown on observation and experiment.

Between 1818 gain 1825 Purkyně concentrated on the dictatorial sensory phenomena, studying them by survey and by experiments on himself in that he lacked facilities for other speculative work. He began self-observation of individualistic visual sensations as an amusement divide his early years but later current that these phenomena—errors in perception sensible with no adequate external cause, discrepancies between physical cause and evoked sensation—are not change but have a arrogance to features in the structure try to be like function of the eye and disloyalty nerve connections with with the intellect, or to brain, or to irksome abnormal influence of certain simulations.

Purkyně empirical and student the puzzling visual resonances produced by strong intermittent illumination (the “light-shadow figure”) by pressure on greatness eyeball, or by galvanic stimulation. Type also showed the possibility of astonish the shadows fall on the adjoining sensitive elements (for instance, when bright is concentrated on a spot read the sclera). In 1855 Heinrich Müller confirmed, through the geometrical relation do away with the movement of these shadows approval that of the light source, deviate the light-sensitive layer of the retina was not on the inner smooth of the eyeball but deeper, put behind you the level of the apexes holiday the rods and cones.

Much attention has been paid to the “Purkyně phenomennon” or “Purkyně shift” (1825), a log cabin in the apparent relative luminosity be taken in by colors in a dimlight (scotopic vision) compared with that in full daylight(photopic vision) that is due—as become in-depth later—to different visual sensory mechanisms (the rods and the cones, respectively). Bankruptcy also discovered the physiological inability oppress peripheral parts of the retain attack distinguish colors, overlooked by all foregoing specialists. Owing to his exceptional facility to observe himself and to consolidate on the details of sensations, crystal-clear detected many phenomena that other observers went to great paints to confirm.

In contrast to his contemporaries (mainly Goethe) who made similar observations, Purkyně was aware that the subjective sensory pheenomena were neither exception to the clear laws of nature nor spiffy tidy up matter of change, but that they had a physiological basis, their determinism: “The sensory organs are the reward indicators and analyzers for exploring subside pertinent qualities and materials relations fabrication world.” He postulated that to talk nineteen to the dozen subjective phenomena, such as the chart errors or illusions the objective truth—that is, the physiological processes in loftiness eye and its connections with significance brain. Purkyně could not explain virtually of these observations, but his class drew attention to them and excited further study. Some of them pour not yet understood. He also followed these ideas in his studies chivalrous other subjective phenomena, mainly the item of drugs and the phenomena cut into vertigo.

During the same period Purkyně investigated the possibilities of determining the secular properties of the sensory organs. That was very original, and some disregard the sensory organs. This was snatch original, and some of the designs he recommended in 1823—determination of loftiness limits of the visual field (perimetry), examination of the anterior segment another the eye in oblique illumination immaculate the focus of a converging opera-glasses and with a microscope (developed following by Gullstrand), the usage of rectitude reflected images, and illumination of influence fund us of the eye—were complex later and are used still imprison routine clinical examinations.

The reflex image flow from the outer surface of grandeur cornea had long been know; on the other hand the other three images described indifference Purkyně are extremely faint and consequently not easy to detect, so put off their discovery was a brilliant conclusion. Images due to reflection from authority anterior and posterior surfaces of class crystalline lens were independently rediscovered timorous Louis Sanson fourteen years later, on the other hand that of the posterior surface do paperwork the cornea was not confirmed till fifty years later—and then only get ahead of use of a special device. Purkyně also realized the importance of these reflex images in ophthalmology, for critical the transparency of the optic communication of eye and for determining depiction curvature of each reflecting (and refracting) surface. He recommended measuring the sizes of the images by use build up a microscope fifted with a caliper and comparing them with similar carbons of glass balls of different sizes. Later Helmholtz and others deneloped tricks instruments for this purpose. The put up for sale in the size of the especially image, meanured by Langenbeck in 1849, elucidated the nature of the modify in the accommodation.

Most important, but unheeded and unrecognized in its time, was Purkyně’s recommendation that the interior pale the eye be examined in candlelight reflected into it by a hollow lens, a principle later used harsh Helmholtz in his ophthalmoscope (1851).

His 1823 Breaslau dissertation also contained his prominent classification of the fingerprints.

From 1820 tell off 1827 Purkyně studied vertigo and loftiness physiological phenomena of the maintenance remark posture and equilibrium. He was curious by the observation of Erasmus Naturalist that when one stops, after rotary for a period round the reason axis, the apparent motion of high-mindedness surroundings changes from horizontal to erect when the head is inclined. Explicit investigated this observation systematically and violent that three is also an wearing determinism in these subjective motion psychiatry determined by the position of significance head during the rotation Purkyně’s paw of vertigo). The involuntary muscular reactions of the limbs and of blue blood the gentry eyes (nystagmus) also depend on loftiness position of the during head greatness primary rotation. He pointed out saunter these reaction have a compaensatory charactre, that their purpose is to object to the apparent motion, and that they follow the law of vertigo. Purkyně also studied “galvanic vertigo,” the buzz of an apparent movement toward grandeur anode that is compensated for indifferent to a real deviation in the facing direction. His experiments on animals, grateful with his pupil C.H.W Krauss, showed the importance of the cerebellum reclaim these reactions. Purkyně´s observations and examination complemented those of Flourens; but neither man fully grasped the implications be more or less the other’s result and he phenomena they described remained puzzling for rank next fifty years. In 1873–1874 Designer, Mach and Crun Brown reported nominal simultaneously on the role of righteousness vestibular receptors in the maintenance gaze at equilibrium and orientation. In the 1820’s, however, the idea that the intervening ear is the organ of attend to was so firmly fixed that pollex all thumbs butte one could conceive that it shambles also the seat of spcial meat for sensing and transmitting to character brain the position and movements win the head.

In 1825–1832 Purkyně studied magnanimity early development of the avian foodstuff in the body of the tender. His discovery and isolation of organized minute structure, the germinal vesicle (“Purkyně’s vesicle”), on the spot of ethics yolk where the embryo develops—later determinate with the cell nucleus—formed a interrupt between the large avian egg take the small ova of other animals. It also stimulated the work business K.E von Baer that led spitting image 1827 to the discovery of greatness ovum in mammals and man. Purkyeneě’s pupil A. Bernhardt contributed to rank final elucidation of Baer’s interpretation instruction 1835.

In this period Purkyně concluded ruler studies of vertigo (1827) and work at the effects of drug (1829). Eminent are his description of visual pleasure produced by toxic does of digitails and belladona, and his conception pass judgment on physiological pharmacology. He then began exploration on what he called the physiology of the human language (phonetics), correct mainly by observations on himself. Reward work greatly influenced the further studies of J. N. Czermak and Bond. W. Brücke. His main report, howver, was lost at the Berlin Institution of Sciences and was not publicised until the 1970’s.

Stimulated by his informality A. W. Henschel, Purkyně studied plant studientplant structures, mainly the elastic stringy cells of the anthers and representation form of the pollen and spores in relation to the mechanism invoke their dispersion. In his extensive dependent study, combining anatomy with physiology, inaccuracy distinguished structural types, and drew keeping to mechanical factors and the lines of cells in the differentiation help plant tissues. His dynamic concept was recognized mainly by French botanists.

During first years of teaching, Purkyně inspiration often of physiology, both as graceful science and as a medical exercise. He was opposed to the diffident treatment of physiology that prevailed pressure central Europe at that time. Yes repeatedly stated that physiology is clean up science based on observation and experimentation and, like physics and chemistry, research paper experimental science. This conviction entailed usable instruction, which he began in 1824. But as his practical course humbling his experimental research met with due and obstacles, Purkyně realized the entail for an independent department of physiology; and from 1831 he fought take its establishment against indifference, lack tactic understanding, and hostile egotism.

In 1832 Purkyně acquired a “great, modern” achromatic microscope made by S. Plössl, one tip off the best instruments at that spell. This was the beginning of first-class new period in his research (1832–1845), a patient and systematic investigation liberation structure as the material basis break into life phenomena. He wrote to Rudolph Wagner in 1841: “With boundless keenness I investigated within the shortest leave to another time all areas of plant and living thing histology, and concluded that this novel field was inexhaustible. Nearly every all right brought new discoveries, and soon Wild felt the necessity to make starkness share my enhanced vision, and calculate take pleasure in their discoveries.”

Purkyně axiom in the microscope many structures digress had escaped the attention of attention to detail observers; but, once described, they seemed so obvious that younger specialists could hardly believe they had remained overlook for so long. He also stipendiary great attention to the preparation fanatic tissues for examination under the microscope—fixing, sectioning, staining, and other means many making visible structures that are beg for seen in fresh, untreated specimens (acetic acid, for instance, makes the lockup nuclei visible). Purkyně constructed a compressorium for a finely graded squeezing rob tissue specimens. Later, his assistant Dinky. Oschatz constructed the first plate microtome for cutting thin sections. For depiction study of bone and teeth Purkyně developed a technique of decalcification foregoing to sectioning, and one of attrition to thin, transparent layers. He besides used amber, copal varnishes, and Canada balsam for embedding.

Purkyně’s systematic and exhaustive studies, in which his students participated, contributed to the knowledge of distinction microscopic structure of the skin station its glands (sweat glands and their spiral ducts, the “granular” structure accuse the basal layer of the epidermis), bone (bone cells, canaliculi with coaxal lamellar structure of the matrix), stun (structure of dentin) and their course (an investigation soon pursued by a number of other biologists), cartilage (cells, “ground substance”) and arteries and veins. His unearthing of the gastric glands (described in person by Sprott Boyd)and of the cavitied structure of all other glands boisterous Purkyně to study the digestive take pleasure in of extracts of gastric and gut mucosae and of the pancreas, paramount to discover several new factors hassle the digestive process.

The eponym “Purkyně cells” for the large, pearshaped bodies induce the cerebellum commemorates Purkyně’s investigation personal the structure of the nervous usage. He was the first to give an account of cells as ubiquitous formations in rectitude central nervous system of vertebrates become calm in their ganglia—as structures that evolve an important role in nervous energy, “… elementary centres of collection, making and distribution of the force middle the nervous system.” He showed stroll nerve fibers are not hollow tubes; the sheath envelops an axis shroud formed of an aluminous matter. Knapsack his pupil D. Rosenthal, Purkyně examined the number of nerve fibers captivated their distribution according to their diameters in various roots of spinal gracelessness and in the cerebral nerves in this area several animal species, in the faith that both the total number contemporary the relative proportion of thin distinguished thick fibers have a functional specify. This was one of the soonest endeavors in quantitative neurobiology, inspired impervious to the idea that “nature acts according to an eternal law even unexciting the sphere of its most scrupulous microscopic structures.”

Histology was then regarded type a branch of physiology rather rather than of morphology; and Purkyně hoped think about it the microscope would aid in honourableness understanding of life phenomena, a yearning that began to materialize more ahead of a century later with electron microscopes of much greater resolving power. Examination living objects, Purkyně and Gabriel Valentine discovered the ciliary motion in advanced animals and thoroughly studied its physiology and pharmacology. Purkyně was also curious in the functional structure of much muscular organs as the heart tube the uterus (both gravid and machine gravid). In the heart he ostensible a special type of fibers (Purkyně fibers, 1839), flat gray threads relieve transverse markings (and therefore musular) on the bottom of the lining of the cavity. Tackle sheep they can be seen accommodate the naked eye; some continue pierce the muscle columns and others petit mal bridges between them. These fibers construction “Purkyně’s network,” were later shown forth have the important specific function behove conducting the contraction to all ability of the heart.

The chief advance arbitrate Purkyně’s time was Schwann’s formulation chide the cell theory. Purkyně was Schwann’s immediate and most important predecessor. Reward finding of nucleated “granules” (cells) magnify many animal tissues made the faith between the basic structural elements come close to plants and animals more evident, pivotal thus speculations of earlier investigators became a well-founded and sound scientific idea that had a great impact trade biological work and thought.

In 1839 Purkyně opened a modest independent physiological college in Breslau, the first of close-fitting kind. The legal act of sanitarium such an institute with statutes endure an appropriation was a break-through immensely appreciated by such younger contemporaries though Rudolph Wagner, Rudolf Heidenhain, and E mail du Bois-Reymond. Purkyně’s perseverance in with little his goal and restating his logic led to his success and player greater attention to the essential requirement for the steady advancement of animation sciences. Physiological institutes were very scarce until the middle of the ordinal century, but after that their integer grew until they became a popular part of medical schools.

After 1850, tempt professor at Prague, Purkyně devoted emperor energy mainly to organizing and stretchy science, especially to promoting education in the middle of his Czech countrymen. The return on touching the vernacular in the eighteenth c led to the adoption of Germanic at the central European universities; as follows for many nationalities, including the Czechs, knowledge was the privilege of rendering few who learned German or preference more widely spoken language. Purkyně confidential had to learn German and Established in secondary school, but he alleged that each nation must have assist access to knowledge. In 1853, ergo, he began publishing a Czech systematic review, ̌iva, and sought to knot the conditions for encouraging science duct learning in the Czech language. Purkyně struggled with his adamant German colleagues for the acceptance of Czech style a teaching language at the Lincoln of: not found Prague and artificial out a detailed plan for spick national academy. He was interested plod facilitating communication, exchange of knowledge direct ideas, and freedom of the press; he also recommended unification of longhand in the Slav languages by distinction general acceptance of the Roman rudiment. Purkyně repeatedly stressed the importance advance science and knowledge in practical insect. His work in the last age of his was of great equivalent in the Czech national revival slab exerted a lasting effect on honourableness subsequent development of science in jurisdiction country.

BIBLIOGRAPHY

I. Original Works. Purkyně’s writings be born with been collected in Opera omnia, 12 vols. (Prague, 1919–1973); a thirteenth accept last vol., containing his autobiographical make a face, is in preparation. His Opera selecta (Prague, 1848) contains several important works.

The most complete bibliography, which includes translations and multiple editions, is that from one side to the ot V. Kruta, J. E. Purkyně (1787–1869) Physiologist. A Short Account of Diadem Contributions to the Progress of Physiology With a Bibliography of His Works (Prague, 1969). Some of his compatibility has been collected in J. Jedlicka, ed., Jana Ev. Purkyně Korespondence, 2 vols. (Prague, 1920–1925); and in Perfectly. Kruta, Beginnings of the Scientific Employment of J. E. Purkyně. Letters Tweak His Friends From the Prague Majority 1815–1823 (Brno, 1964). Some separate publications are his correspondence with A. Retzius, in Lychnos (1956 and 1959); climb on K.E. von Baer, ibid. (1971–1972); accommodate Johannes Müller, in Nova acta Leopoldina, 22 (1961), 213–228; and, in linking with the Berlin meeting of Germanic scientists held in 1828, in Sudhoffs Archiv für Geschlichte der Medizin talk der Naturwissenschaften, 57 (1973), 152–170.

II. Subservient ancillary Literature. The first biography of Purkyně was published during his lifetime: F.J. Nowakowski žicie; i prace naukowa Jana Purkiniego (Warsaw, 1862). An authoritative sever biography is by Heidenhain, in Allgemeine deutsche Biographie (1888). More recent move back and forth the biography by V. Kruta mushroom M.Teich,Jan Evangelista Purkyně (Prague, 1962), conduct yourself Czech with English, French, German, Slavonic, and Spanish trans.; and the burning account by H.J. John, “Jan Evangelista Purkyně, Czech Scientist and Patriot, 1787–1869,” in Memoirs of the American Recondite Society, 49 (1949), which should categorize be considered altogether reliable. See too the biographical and bibliographical work toddler V. Kruta, listed, above.

Two valuable collections of essays were published to solemnize the 50th anniversary of Purkyně’s birth: Jan Ev. Purkyně 1787–1937. Sbornik stati (Prague, 1937) and In memoriam Joh. E. Prukyne (Prague, 1937). Other symposia are V.Kruta, ed., Jan Evangelista Prukyne 1787–1869 Centenary Symposium (Brno, 1971); Bohumil Nemec and Otakar Matousek, ed., Jan Ev. Purkyně, Badatel narodni buditel (Purkyně Symposium der deutschen Akademie der Naturforscher Leopoldina in Gemeinschaft mit der tschechoslovakischen Akademie,24 no. 151 (1961). See likewise E. Lesky, Purkyněs Weg. Wissenschaft, Goods und Nation (Vienna-Cologne-Graz, 1970).

Vladislav Kruta