American J o u r n a l of Medical Genetics 401-25 (1991)
Historical Study: Johann Gregor Mendel 1822-1884 F’ranz Weiling Bonn-Lengsdorf, Germany ~
The life and personality of Johann Gregor Mendel (1822-1884), the founder of scientific genetics, are reviewed against the contemporary background of his times. At the end are weighed the benefits for Mendel (as charged by Sir Ronald Fisher) to have documented his results on hand of falsified data. Mendel was born into a humble farm family in the “Kuhlandchen”, then a predominantly German area of Northern Moravia. On the basis of great gifts Mendel was able to begin higher studies; however, he found himself in serious financial difficulties because of his father’s accident and incapacitation. His hardships engendered illness which threatened continuation and completion of his studies until he was afforded the chance of absolving successfully theological studies as an Augustinian monk in the famous chapter of St. Thomas in Altbrunn (Stare Brno). Psychosomatic indisposition made Mendel unfit for practical pastoral duties. Thus, he was directed to teach but without appropriate state certification; an attempt to pass such an examination failed. At that point he was sent to the University of Vienna for a 2-year course of studies, with emphasis on physics and botany, to prepare him for the exam. His scientific and methodologic training enabled him to plan studies of the laws of inheritance, which had begun to interest him already during his theology training, and to choose the appropriate experimental plant. In 1865, after 12 years of systematic investigations on peas, he presented his results in the famous paper “Versuche uber Pflanzenhybriden.” Three years after his return from Vienna he failed to attain his teaching certification a second time. Only by virtue of his exceptional qualifications did he continue to function as a Supplementary Professor of Physics and Natural History in the two lowest
Received for publication September 12, 1989; revision received October 1, 1990. Address reprint requests to Universitats Professor Dr. rer. nat. Dr. hum. lett. Franz Weiling, Zur Marterkapelle 65, D-5300 BonnLengsdorf, Germany.
0 1991 Wiley-Liss, Inc.
classes of a secondary school. In 1868 he was elected Abbot of his chapter, and freed from teaching duties, was able to pursue his many scientific interests with greater efficiency. This included meteorology, the measurement of ground water levels, further hybridization in plants (a.0. involving the hawk week Hieracium up to about 1873),vegetable and fruit tree horticulture, apiculture, and agriculture in general. This involved Mendel’s active participation in many organizations interested in advancing these fields at a time when appropriate research institutes did not exist in Brunn. Some of the positions he took in his capacity of Abbot had severe repercussions and further taxed Mendel’s already overstressed system. The worst of these was a 10year confrontation with the government about the taxation of the monastery. Attempts to conciliate (a.0. by appointing Mendel first as Vice-Director, then as Director of the Moravian Mortgage Bank) did not alter Mendel’s position. The recently-dated genetic note-sheet shows that Mendel was preoccupied with the interpretation of the results of his Pisum experiments till the end of his life.
KEY WORDS: Mendel-life and personality, history, heredity and plant breeding experiments, Pisum, genetics, origins; apiculture, meteorology, dating the genetic note-sheet, Mendel-a forger of data? INTRODUCTION Modern genetics has attracted the interest of numerous investigators, as well as the fascination of many lay persons, in part due to the complexity of its science, possibilities of its application, and its methodologicchallenges. The story of the discovery of the fundamental laws of genetics over 120 years ago by the Augustinian monk Johann Gregor Mendel is still of interest and importance to science and to mankind in general. Following the “rediscovery” of the laws presented by Mendel in 1865 (and published in the following year as
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“Versuche uber Pflanzenhybriden”) [Mendel, 1865a,bl, confirmation was brought in all areas of plant, animal, and human life. However, hardly any of Johann Gregor Mendel’s discoveries have raised so many questions; their elucidation took decades while the appreciation of the discoverer Mendel fluctuated between highest recognition and virtually complete oblivion or misinterpretation. Thus we may pose the following questions: 1)Exactly how did this monastic priest arrive at this biological core question and its elegant solution; 2) how is it possible to explain that his discovery and knowledge about his person remained unknown for such a long time that it took decades of research to arrive at a half-way satisfactory answer; and 3) how was it possible for the founder of modern statistics, Sir Ronald Aylmer Fisher (18901962),to conclude in 1936 that “the data of most, if not all, of his experiments have been falsified, so as to agree closely with Mendel’s expectations” [Fisher, 19361, whereas the interpretation of his experiments is accepted as valid. During the past 20 years this statement caused Mendel to be widely accused of falsifying his data [Weiling, 19851 (Fig. 1). The following is an attempt to offer an answer corresponding as closely as possible to our present knowledge.
two dcughters [Weiling,1983~1. His birthplace Heinzendorf (Czech: HynEice) in the Kuhlandchen, was located in the border area of that small part of Silesia which remained with Austria after the Silesian wars (17401742, 1744, 1756-1763) fought between King F’rederick I1 of Russia and Empress Maria Theresia of Austria. Thus, in practically all later official documents, Mendel was referred to as a Silesian (Sil.: Silesius). Ecclesiastically, Heinzendorf belonged to the Moravian parish of Gross-Petersdorf (6s: Vrazne) located about a half hour away. Its parish priest, Johann A.E. Schreiber (1769-18501, had a special interest in natural history and was known as an expert fruit grower; he had a lasting influence on the boy Mendel’s development [Weiling, 1984el. It was Schreiber, more than anyone else, who recognized the gifts of the young Johannes and persuaded his parents to release their only son for higher education in spite of their constrained financial situation. Initially Mendel attended the village school in Heinzendorf. At the age of 11 (1833) he transferred into the third grade of the Piarist Central School in Leipnik (Cs: Lipnik) and in the following year he was sent to the Gymnasium in Troppau (Opava) where he completed all 6 years successfully. At that time the Austrian school system provided in the public gymnasia four grammar classes followed by MENDEL’S LIFE two classes in the humanities always taught by the same Johannes (his birthname) Mendel was born on July 20 grammar and humanities instructor over the entire or 22,1822, the only son of peasant farmers who also had 6-year cycle. This teacher taught all subjects (Latin,
Fig. 1. The “Rogues’gallery” of Wade [Wade, 19831 including Johann Gregor Mendel.
Mendel Greek, geography, history, and mathematics) for 18 hours per week; 2 hours per week were devoted to mathematics [Timp, 19681. The prefect at that time, who also functioned as religion in$ructor, was an Augustinian Father of the Altbriinn (Cs: Stare Brno) chapter [Weiling, 1984al. At that time natural history was not a didactic subject in the school system. However, Mendel had the opportunity to regularly visit the Museum of Natural History of the school (today Schlesisches Landesmuseum) (cs: Slezske Muzeum Opava) which had been founded in 1822. There he was, presumably, of great assistance to its director and co-founder (also grammar teacher) Professor Faustin Ens (1782-1858), in caring for and developing the collections [Weiling, 1983al. The support which the parents were able to offer their son was restricted to regular “care packages.” However, these stopped when Mendel’s father became incapacitated after a severe accident and finally had to turn the running of his property over to his son-in-law. In his Autobiography [Mendel,18501Mendel wrote that “after several disasters following in rapid succession. . . his parents became completely unable to pay for the necessary expenses of [his] studies” (Fig. 2). Mendel tried to stave off his direst needs by offering remedial tutoring for which he had been approved through a special examination after a private course. Nevertheless, his constant deprivations led to a severe illness which forced him t o rest in his parents’ home from Pentecost till September in 1839 [Iltis, 19241. Mendel’s miserable existence did not improve after completion of his gymnasium studies in the middle of 1840and matriculation into the 2-year course of philoso-
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phy at the Philosophical Institute of the University of Olmutz (Olomouc). This course of studies included philosophy, Latin and Greek philology, mathematics, physics, religion, as well as the facultative fields of natural history and history. Greek, physics, and history were taught in the third and fourth semesters. As a stranger in town Mendel found no opportunity of supporting himself through remedial instruction [Mendel, 18501. He became ill during the final exams of the first semester, after having passed the examinations in mathematics and Latin philology with highest grades (Fig. 3). Thus, Mendel lost not only credit for the entire year, but also the free time granted to him till then for his studies. The spring and summer of 1841were apparently spent recuperating in his parent’s home, according to his Autobiography, even “a full year.” It was only when his younger sister Theresia offered him a portion of her inheritance that he was able to renew his studies in 1842 [Weiling, 19881, now as a paying student. “Using all of his strength he succeeded this time t o complete his two years of study” [Iltis, 1924, Mendel, 18501. He attained the highest grade in all courses (e = eminens) except for theoretical and practical philosophy, in which he got the second-best grade (1=prima classis). Thus, it appears that the practical courses, especially mathematics and physics, had a much greater interest for Mendel than a more speculative field such as philosophy, a conclusion supported by the qualifiers used to describe his efforts (“by application”) (Fig. 3). In this connection it is important to note that of the 20 or so hours of classes attended per week in Olmutz, 7 and 8, respectively, were devoted to mathematics in the first year and t o physics in the second both were areas of
Fig. 2. Final portion of Mendel’s handwritten account of his life [Mendel, 18501submitted by him to the Examination Commission of Vienna together with other documents.
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Fig. 3. Excerpts of the records of studies of the Philosophical Institute of the University of Olmutz with the entries pertaining to Johann Mendel. A the year 1841;B: the years 1842 and 1843 (State Archive Olomouc, Czechoslovakia). During the earlier attempt Mendel had the number 49,during his subsequent course (as repeater) the number 42.
special importance to him in his later scientific career. Mendel’s mathematics instructor was Professor Johann F’ux (1785-1848) [Weiling, 1984fl (Fig. 4) who was widely known for his textbooks; his physics instructor was Professor Friedrich F’ranz (1796-1860) [Weiling, 1983b1, a Prqmonstratensian and later Abbot of Neureisch (Nova Ris6). Before his appointment in Olmiitz (1842), F’ranz had taught physics for 19 years a t the Philosophical Institute in Briinn, and during that time he had lived in the Altbriinn monastery of the Augustinians [Weiling, 1982al. Franz gave Mendel a solid character reference, in fact referred to him “as almost the best” in physics [Iltis, 19241.On his recommendation Mendel was accepted as a novice in the Altbriinn chap-
ter after completion of his philosophical studies (1843). This freed him at once of his struggle for existence and “courage and strength returned with that level of comfort desirable for all studies” [Mendel, 18501. In his Autobiography Mendel wrote that his condition decided on his change of status. This was not meant to refer to the priestly state, as has sometimes been assumed, but rather to the monastic state, i.e., membership in an order. In the contract (1842) in which Mendel’s father turned over his home and farm to his son-in-law,he also makes provision for his son Johann in case he were “to follow his wishes and enter the priestly state” and in case he would be “prevented through a disease” from “attaining the priestly state’’ [Iltis, 19241.
Mendel
i b c r
Irit@tuetiP nab aiebctc %leebra.
--#wwwwMSImQe, 1839. ;Drub u n b ‘ p a p t t r @ o n 2ldlIol6 e r a r n i b f .
Fig. 4. The textbook of Arithmetic and Basic Algebra from the series on pure mathematics by Johann Fux, Olmutz, 1839.
After completion of his novitiate, Mendel absolved his theological studies between 1844 and 1848 at the Episcopal Seminary in Briinn. On August 6, 1847 he was ordained a priest. During the course of his studies he also completed a l-year (1845-1846) agricultural curriculum (Fig. 5) at the Philosophical Institute in Briinn under Professor Franz Diebl (1770-1859). At the same time he attended a semester course on fruit growing and viniculture (Fig. 6). At the beginning of the 19th century (however,not at Mendel‘s time anymore) these additional studies were required of theology students, since the Austrian government intended the rural priesthood to effectively teach and pass on their agricultural knowledge to the local population. These studies were also in the best interest of the Altbriinn monastery with its own agricultural domains, and thus of its Abbot, Franz Cyril1 Napp (1792-1867) [Weiling, 1968, 1971bl (Fig. 7). After a brilliant performance in his professional examinations of the theological Faculty of the University
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of Vienna, Napp was appointed Professor of old-testamentary hermeneutics and ancient Oriental languages (including Arabic, Syriac, and Chaldean) at the Theological Institute in Briinn. In 1824 Napp has been elected Abbot and quickly mastered the administrative1 economic duties of the monastery. He was a member of the Executive Committee of the Moravian-Silesian Agricultural Society; Director of the Pomological Society (as of 1827),the predecessor of the later section for fruit, horticulture, and viniculture of the Agriculture Society; and, as of 1849, Vice-Director,and in 1865 the General Director of the Agricultural Society. As such, Napp manifested not only profound technical knowledge and interests, but also proved himself to be a skillful judge of people and a splendid organizer. And as the Director of the State Gymnasia of Moravia and Silesia he was for many years the supervisor of higher education until the reorganization of the Austrian school system after the revolution of 1848. Not only Napp, but also other members of the chapter held public office. Thus, the chapter had to provide the professors of philosophy and mathematics at the Philosophical Institute in Briinn and to keep appropriate candidates ready for these positions at all times [Weiling, 1982al. Even for the chair of Natural History and Agronomy the monastery was prepared to provide a trained candidate after the vacancy of 1825-1828 [Weiling, 19761. It is t o be expected that the theology student Gregor Mendel was in constant contact with these obligations of the chapter, particularly since he himself additionally completed the entire agriculture curriculum then available. In his Autobiography he emphasized that during his theological studies he had dealt with botanical and natural-historical problems in the framework of the available opportunities and that, as a consequence, his liking for natural history increased greatly. With great likelihood Mendel was also confronted during these years with questions of heredity, i.e., the question of how, according to which rules, above all valuable traits are transmitted from generation to generation, and how crossing of sorts and types could combine and increase valuable traits. Astonishing results of some sheep breeders in the Briinn area had regularly occasioned detailed discussion of these problems in the 1820s and 1830s at the meetings of the Agricultural Society; even at the beginning of the 1840s they were a subject at an international scientific meeting at which Napp participated substantially in the discussion [Weiling, 19881. Botanically, the problem of plant improvement through crossing, especially in fruit growing, was of special interest. But also the efforts in collecting extensive assortments of different types, e.g., in sheep breeding (wool improvement) and in viniculture (Fig. 8), pointed in this direction and may have been ofinterest to the young Mendel. Soon after completion of his theological training the young Mendel turned out to be little fit for practical pastoral duties. According to a report by Napp to the Bishop of Briinn “at the bedside of the ill and suffering [Mendell was overcome with a paralyzing shyness, and he himself then became dangerously ill” [Iltis, 19241.
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Fig. 5. “Report card” concerning the outstandingly successful performance by Mendel during the second semester of the study of agriculture at the Episcopal Philosophical Institute of Briinn. The certificate is signed not only by the instructor Professor Diebl, but additionally by the certifying commissioners of the Bishop and of the Moravian Silesian Agricultural Society.
Therefore he was freed up for teaching and in September 1849 he was appointed adjunct instructor at the Gymnasium in Znaim (Znojmo)where he taught Latin, Greek, German, and mathematics during the winter semester [Kfiienecky, 1965; Czihak, 19841. However, since he lacked the required state qualifications to teach, at the urging of the Director of the School after
this semester he applied to the appropriate agency in Vienna to take the examination in Natural History for all grades, but in physics only for the lower grades. Mendel did not pass this examination; however, the notification, dated October 17, 1850, was not forwarded to him till August 1851 [Weiling, 19861. At the advice of Professor Andreas von Baumgartner (1793-1865) (Fig.
Mendel
t. f. ')lroiqTor bcr P~nbmirtl)id)~ft6kf)reunb aUjemcintn %JtUrl 8ef4iete Jn Err pl)ilofop$ifd)en EtlpnPdlt iu Brdiin unb Binit0 glirte mef)rrrer IunEloirt~f@JftlidW@efCuid)aften 3nns
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Fig. 7. Prelate Franz Cyril1 Napp in contemporary clerical garb.
unb %u6lanbe&
-a-
---
- ----=-==zT;;&-- _ _
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SrCitut 1644, Bcbrudt bei %ubolp$ %ol)rer'4 f d Bittior. Fig. 6. Professor Diebl's textbook of arboriculture, especially pertaining to fruit trees, viniculture, and forestry, Briinn, 1844.
9) who had been the examiner in physics but in the meantime had been appointed the Austrian Minister of Commerce, Mendel enrolled as a special student for further studies a t the University of Vienna. During the reorganization of higher studies in Austria after the revolution of 1848 the philosophical institutes had been dissolved; they existed only in locations where there was also a seminary since theological training had t o be preceded by attendance a t a philosophical institute. The natural-historical subjects of these institutions were transferred to the gymnasia whose curriculum was thereby expanded by the 7th and 8th grades. In order to meet the need for appropriately trained instruc-
tors, chairs were created or reorganized, primarily within the philosophical faculty of the University of Vienna, in order to offer required courses in physics, botany, zoology, and chemistry [Weiling, 19861. Thus, in Vienna a new Physics Institute was created under the direction of Professor Christian Doppler (1803-1853) (Fig. 10); it began instruction late in the winter semester 1851-1852 in a recently completed and newly equipped institute building. We are particularly well-informed on the operations of this institute because it was based on regulations which had been formulated by the Ministry on the basis of a draft requested by Doppler. Accordingly, the maximally three semester-long training courses in physics consisted of 2 hours per day of active classroom instruction, with the entire rest of the day devoted to individual demonstrations or research projects. In this connection each of the candidates, after completing the work and experiments required for school instruction, was to perform an individually assigned project. These projects were to include the appropriate library research, the experimental design and protocol, as well as a final report under continuous supervision and eventual evaluation and correction by the Director of the Institute. In addition, these research papers were to be submitted to the Ministry at the end of academic year together with the Director's progress report [Weiling, 19861. Mendel began his studies in Vienna late, 4 weeks after the beginning of the semester, however, in time for the
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Fig. 8. List of the type of grapes grown close to the chapter of St. Thomas, Altbriinn [Mittheilungen, 1868, No. 21, May 1830, pp 166-1671. During the first half of the 19th century there were similar collections of grapes in two other places in Brunn.
opening of the Physics Institute. As a special student (ausserordentlicher Eleve) he attended exclusively the Physics Institute during the first semester and part of the interval between semesters. It may have helped Mendel that, like Mendel, the Assistant a t the Institute, Franz Pekarek, who held this position over the next several years, had also been active as an adjunct instructor during the winter semester 184911850 at the Gymnasium in Znaim. Only during his second semester did Mendel take additional courses: plant morphology and systematics in botany under Eduard Fenzl (1808-1879) (Fig. 91, and systematics and lab in zoology under Rudolf Kner (1810-1869). However, there were some scheduling
conflicts with physics. During the third semester it was not possible for Mendel t o attend the lectures announced by Doppler who became ill and died shortly afterwards (1853). Doppler was immediately replaced by Professor Andreas von Ettingshausen (1796-1878) (Fig. 9) under whose direction the practical projects at the Physics Institute remained considerably restricted during the first few years. During this semester Mendel took most of his non-physical courses: under F'ranz Unger (18001870) (Fig. 9)anatomy and physiology of plants as well as the first lab course at the University of Vienna in botanical microscopy; under Josef Redtenbacher (18101870) (Fig. 9) general and pharmaceutical chemistry as well as methods of chemical analysis. In addition he
Mendel
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Fig. 9. Group portrait of the members of the mathematical-historical class of the Academy of Sciences in Vienna (about 1855)[Meister, 1947, plate 19, with five of Mendel’s teachers A.v. Baumgartner (second sitting from left), A.v. Ettingshausen (first sitting from left), E. Fenzl (fifth standing from left), F. Unger (first standing from right), J. Fkdtenbacher (fourth standing from left).
attended two 1-hour lectures on paleontology as well as a 1-hour lecture on logarithmic-trigonometric tables. During his fourth and last semester Mendel took von Ettingshausen’s course on introduction to and use of physical instruments and higher mathematical physics, and Redtenbacher’s course on organic chemistry. In addition, he established connection, perhaps as early as the second semester, with the zoological division of the Court Natural History Collection and its director Vinzenz Kollar (1797-1860). This resulted in a paper which Mendel presented on July 21,1853, a few weeks before his final return to Brunn, before the ZoologicalBotanical Society of Vienna [Mendel, 1853; Weiling, 19861. Thus, Mendel’s studies in Vienna were primarily devoted to physics, having worked completely or extensively at least 1full year in the Physics Institute under Doppler. Doppler died early, but here Mendel may have acquired his later so successfully applied scientific method, especially since it can be assumed that during the first year of the newly created Institute Doppler proceeded strictly according t o the rules of the Institute, largely due to his own initiative. In addition, Doppler was far more practically oriented, and didactical in his mode of work, than his successor von Ettingshausen. Since the rules of the Physics Institute contain detailed instructions to study the literature and since it can be assumed that Mendel personally acquired at the latest during his stay in .Vienna C. F’r. von Gartner’s (1772-1850) book: “Uber die Bastarderzeugung i m PfZanzenreich” (concerning the production of hybrids in the plant kingdom, 1849; Figs. 11, 12); it can be concluded that under the influence of that book Mendel read the paper he later quoted by J. G. Kolreuter
(1733-1806) [Kolreuter, 1761-17661, W. Herbert (1778-1847) [Herbert, 18371,and H. Lecoq (1802-1871) [Lecoq, 18451, probably accessible only in Vienna. We can therefore assume that Mendel made the detailed plans for his later Pisum experiments in Vienna, and began them, i.e. obtained and tested the various types and sorts of seeds, immediately after his return to Brunn. However, upon return t o Brunn (18531, Mendel did not, as might have been expected,present himself for the final exam, but only 3 years later when difficulties arose in the as yet incomplete Oberrealschule in Brunn where he taught without having taken the exam. Mendel did not pass this exam either. According to Kfiienecky [19631 a t the beginning of the written exam on May 5, 1856in Vienna, Mendel became so ill that he was unable to write and gave up. It is known that Mendel was in poor health while preparing for the exam presumably through overexertion. Now he became so ill that, in spite of difficult travel conditions, his father and uncle rushed over 120 km from Heinzendorf to support him [KEiienecky, 19651. Thereafter Mendel did not attempt to repeat the exam, and the Director of the Oberrealschule, Josef Auspitz (1812-1889) was evidently able, on the basis of Mendel’s exceptional pedagogic performance and in the face of the official rules, to retain him as a professor at the school (Fig. 13). Mendel informed the Munich botanist Carl Nageli (1817-1891) on April 18, 1867 that he had performed the actual experiments of his Pisum work from 1856 until 1863, inclusively [Correns, 19051. In contrast to Fisher 119361 (who later corrected himself) [Fisher, 19551and in agreement with Orel [Orel, 1971al it may be assumed that the first crosses were performed in
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Fig. 11. Carl Friedrich von Gartner [Stubbe, 1965, p 1021.
netic study on differences in flowering time) intended for publication were concluded in 1863 to obtain “space and time for the cultivation of other experimental plants” [Correns, 19051. At that time infestation with the pea beetle Bruchuspisi was so heavy that beginning in 1864 substantial damage was recorded and in 1865 barely 20-25% of harvested peas were uninvolved. He mentions in the same letter that in the vicinity of Brunn the cultivation of peas had to cease altogether. The final analysis of his experiments and the preparation of the manuscript probably occurred in 1864. MenFig. 10. Bust of Christian Doppler in the courtyard of the Univer- del reported on his work in detail t o the Naturforschende sity of Vienna. Verein of Brunn (founded in 1861) a t the sessions of February 8, and March 8, 1865. Mendel’s paper was printed in the volume of Proceedings for the year 1865; however, it appeared only toward the end of 1866 (Fig. 1856. This would involve at least the 118 crosses per- 15).The reason for this delay was the war of 1866 [Weilformed on 25 pea plants, with the traits smooth and ing, 1970~1, which visited on Brunn a temporary occupawrinkled seeds respective green and yellow seed color, tion by Russian troops, food shortages, and a serious during the year of his disastrous second board examina- cholera epidemic with some 3,000 deaths (1,000 citizens tion. In the two preceding years he had subjected 34 and more than 2,000 Prussians) [Mendel, 18663. Accord“more or less different” types of peas to a test of purity, ing to the information on its yellow covers, this volume and selected 22 types for his subsequent experiments appeared in an edition of 500 copies of which 115 went to [Mendel, 1865a,bl. scientific institutes or libraries [Weiling, 1969133.There In order to appreciate his work during the years of his were 40 reprints of Mendel’s work; the whereabouts of 13 Pisum experiments it must be mentioned that by no of these is presently known [Weiling, 1984~1. means all experiments entered his later publication and Already 6 months after its appearance Mendel’s work that since 1854 he also worked at the Brunn Ober- was cited in the May 14, 1867 issue of the well-known realschule teaching the two lowest classes of Naturlehre botanical journal Flora in a “repertoire of the periodic (Physics) and natural history with, depending on the botanical literature.” In addition, Mendel’s work is number of parallel classes, 18 and 27 hours per week of quoted both in the register of authors as well as in the instruction and 60 to 120 students per class [Programme index of subjects (key words: Bastarde and Hybridittit) of of the Oberrealschule Brunn] (Fig. 14). the volume of this journal [Weiling, 1969133.By 1870one According t o Mendel’s own information (second letter other publication, by 1880 another four, by 1890 a furto Professor-Nageli) all experiments (except for one ge- ther two, and one other by 1900 in the German, Swedish,
Mendel
Fig. 12. Mendel’s personal copy of the book by Gartner. It contains numerous annotations and notes in Mendel’s handwriting, especially on the front fly leaves.
Russian, and Anglo-Americanliterature had cited Mendel’s Pisum work [Weiling, 1971al. A particularly thorough discussion is in the 1874 St. Petersburg dissertation of Johannes Schmalhausen, a descendant of a family originally from Bremen [Weiling, 1966, 1974, unpublished manuscript]. The formerly frequently voiced opinion that Mendel’s work was unknown before 1900 and thus had fallen into oblivion is untenable on the basis of these data. However, the problem of the genetic process itself and its laws lost importance in Brunn because of the increasing cotton industry and simultaneous reduction of the importance of sheep wool. On the other hand, work in cytology, especially by Walther Flemming (1843-1905) a.o., August Weismann (1834-19141, and Eduard Strasburger (1844-1912), yielded detailed knowledge
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on cell division and the behavior of the easily stainable bodies in the nucleus (chromosomes)which appeared to have something to do with the genetic mechanism. The British genius, Sir Francis Galton (1822-19111, who worked extensively with the heredity of human faculties and character traits and developed his own model of heredity, apparently was unacquainted with Mendel’s work. Following the strong recommendation of the influential Munich botanist Carl Nageli, Mendel was induced to begin detailed crosses in Hieracium. However, through behavior which is peculiar to this plant (apogamy) and which was recognized and worked out only much later, the reproductive mechanism functions in a totally deviant manner. New and completely different challenges which Mendel had to meet as of 1868 did not allow him the required time for further systematic genetic investigations. Nevertheless, the Hieracium experiments, presented by Mendel before the Naturforschende Verein in Brunn on June 9, 1869, are remarkable [Mendel, 18691. Hieracium was a difficult genetic subject because of the delicate construction of the individual blossoms; however, the fact that with only one exception all known artificially produced Hieraciurn hybrids derive from these experiments of Mendel attest to his extraordinary experimental skill. From five of six successful hybrids Mendel sent living material including the parental stock to Nageli in Munich. It was propagated in the Munich botanical garden and then was incorporated into the subsequent systematic investigations of Nageli and his coworker Albert Peter (18531937) [Peter, 1884,1885; Nageli and Peter, 18851.Peter included specimens of 11 original forms and 17 hybrid from Mendel’s stock in his four volume herbarium of the Hieraciae [Peter, 1885, 18861 (Fig. 16). Of this work, I was able to track down 26 admittedly in part incomplete specimens in herbaria of 13 different European countries [Weiling, 1969al. On March 31,1868 Mendel was elected the successor of the deceased Abbot Franz Cyril1Napp of the Altbrunn chapter. This brought to an end not only his work as adjunct Professor in the Oberrealschule, but also, after a short phase-out period, the complete cessation of his work in genetics. Administrative and public service obligations predominated, especially in the executive committee of the Moravian-Silesian Agricultural Society. In 1874, a tax law was enacted which obligated monasteries and convents to substantial contributions to the Religious fund from which the State drew means to support the church. Mendel’s protest grew into a protracted and wearisome confrontation. Since he viewed the law as unjust, Mendel, as the only prelate in the Austrian empire, resisted it, in the face of the ensuring confiscation of a substantial portion of the monastery income. After Mendel’s death, his successor compromised; however, he insisted, successfully, on return of the overpayments. At the same time the chapter was relieved of any further payments of this tax, since the true income of the monastery was below the level stipulated by the law. Early in the morning of Epiphany (January 6,1884)
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Fig. 13. A previously little known (incomplete) group portrait of members of the Altbrunn chapter of St. Thomas from a time between 1861-1864 (University Library Brno, Czechoslovakia). This is a different grouping than that in Iltis [1924,plate 41 involving the same persons and taken at the same occasion.Ofthe persons portrayed here, the following were engaged as teachers: Mendel holding a fuchsia blossom; Fr. Thomas Bratranek (standing third from left), for 30 years Professor ofGerman Literature at the University of Krakau, today Krakow, Poland: Fr. Antonin Alt (standing, second from right): elementary mathematics, at times director of the Gymnasium of Troppau (Opava, Czechoslovakia); Fr. Benedikt Fogler (standing, first from the left), instructor of German, Italian, and French at the Oberrealschule in Brunn; Fr. Paul KfiikowskJi (standing second from left), composer, director of the Thurn-Foundation for Musical Education (conservatory) at the Altbrunn chapter (later attended by the famous Moravian composer LeoB JanaEek, 1854-19281, as well as choir director of the Cathedral of Olmutz (Olomouc).
Mendel died of chronic renal disease and heart failure His failure during the first board examination must (Bright’s disease and dropsy according to the death cer- also be regarded as a blow of fate. He had to fail, because tificate) [Kfifenecky, 1965; Weiling, 1984dl. without appropriate specialty training, he had to subject himself t o much higher standards of examination MENDEL’S PERSONALITY which had been improved during the reorganization of Mendel was a multifaceted personality whose life was higher education following the 1848 revolution. marked not only by remarkable successes but also by As a further blow of fate must be regarded the failure great adversities and blows of fate. The severe accident of his second board examination in 1856 which he had to and incapacitation of his father (1838)and other misfor- call off at the very beginning because of severe illness tunes in his family deprived him of financial support for with inability to write with subsequent irregular aphis education. The associated deprivations damaged his pointment as supplementary professor. Apparently his health through inadequate nutrition, illnesses, and re- physical and emotional status had been so badly imduced resistance. This forced him to interrupt his philos- paired by the preceding misfortunes that he was not up ophy studies already during the first semester exams to the additional stress of preparing for and taking the causing him to loose his free study time. He was able to examination. A final blow of fate was the prolonged and wearisome, continue his education only after his sister Theresia gave him a part of her inheritance which allowed him to health-damaging conflict with the government about complete his philosophical studies to take advantage of the religious tax which Mendel, in fidelity to his oath of the subsequent opportunity to pursue a priestly voca- office and his conviction about the illegality of the law, tion as a monk in the Altbriinn Chapter. Mendel believed unable to avoid. thanked his sister by financing the education of her This externally evident professional failure of Mendel three sons, one of whom died during his studies. must be contrasted with the fact that it was his Pisum
Mendel
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Historical Study: Johann Gregor Mendel 1822-1884 F’ranz Weiling Bonn-Lengsdorf, Germany ~
The life and personality of Johann Gregor Mendel (1822-1884), the founder of scientific genetics, are reviewed against the contemporary background of his times. At the end are weighed the benefits for Mendel (as charged by Sir Ronald Fisher) to have documented his results on hand of falsified data. Mendel was born into a humble farm family in the “Kuhlandchen”, then a predominantly German area of Northern Moravia. On the basis of great gifts Mendel was able to begin higher studies; however, he found himself in serious financial difficulties because of his father’s accident and incapacitation. His hardships engendered illness which threatened continuation and completion of his studies until he was afforded the chance of absolving successfully theological studies as an Augustinian monk in the famous chapter of St. Thomas in Altbrunn (Stare Brno). Psychosomatic indisposition made Mendel unfit for practical pastoral duties. Thus, he was directed to teach but without appropriate state certification; an attempt to pass such an examination failed. At that point he was sent to the University of Vienna for a 2-year course of studies, with emphasis on physics and botany, to prepare him for the exam. His scientific and methodologic training enabled him to plan studies of the laws of inheritance, which had begun to interest him already during his theology training, and to choose the appropriate experimental plant. In 1865, after 12 years of systematic investigations on peas, he presented his results in the famous paper “Versuche uber Pflanzenhybriden.” Three years after his return from Vienna he failed to attain his teaching certification a second time. Only by virtue of his exceptional qualifications did he continue to function as a Supplementary Professor of Physics and Natural History in the two lowest
Received for publication September 12, 1989; revision received October 1, 1990. Address reprint requests to Universitats Professor Dr. rer. nat. Dr. hum. lett. Franz Weiling, Zur Marterkapelle 65, D-5300 BonnLengsdorf, Germany.
0 1991 Wiley-Liss, Inc.
classes of a secondary school. In 1868 he was elected Abbot of his chapter, and freed from teaching duties, was able to pursue his many scientific interests with greater efficiency. This included meteorology, the measurement of ground water levels, further hybridization in plants (a.0. involving the hawk week Hieracium up to about 1873),vegetable and fruit tree horticulture, apiculture, and agriculture in general. This involved Mendel’s active participation in many organizations interested in advancing these fields at a time when appropriate research institutes did not exist in Brunn. Some of the positions he took in his capacity of Abbot had severe repercussions and further taxed Mendel’s already overstressed system. The worst of these was a 10year confrontation with the government about the taxation of the monastery. Attempts to conciliate (a.0. by appointing Mendel first as Vice-Director, then as Director of the Moravian Mortgage Bank) did not alter Mendel’s position. The recently-dated genetic note-sheet shows that Mendel was preoccupied with the interpretation of the results of his Pisum experiments till the end of his life.
KEY WORDS: Mendel-life and personality, history, heredity and plant breeding experiments, Pisum, genetics, origins; apiculture, meteorology, dating the genetic note-sheet, Mendel-a forger of data? INTRODUCTION Modern genetics has attracted the interest of numerous investigators, as well as the fascination of many lay persons, in part due to the complexity of its science, possibilities of its application, and its methodologicchallenges. The story of the discovery of the fundamental laws of genetics over 120 years ago by the Augustinian monk Johann Gregor Mendel is still of interest and importance to science and to mankind in general. Following the “rediscovery” of the laws presented by Mendel in 1865 (and published in the following year as
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“Versuche uber Pflanzenhybriden”) [Mendel, 1865a,bl, confirmation was brought in all areas of plant, animal, and human life. However, hardly any of Johann Gregor Mendel’s discoveries have raised so many questions; their elucidation took decades while the appreciation of the discoverer Mendel fluctuated between highest recognition and virtually complete oblivion or misinterpretation. Thus we may pose the following questions: 1)Exactly how did this monastic priest arrive at this biological core question and its elegant solution; 2) how is it possible to explain that his discovery and knowledge about his person remained unknown for such a long time that it took decades of research to arrive at a half-way satisfactory answer; and 3) how was it possible for the founder of modern statistics, Sir Ronald Aylmer Fisher (18901962),to conclude in 1936 that “the data of most, if not all, of his experiments have been falsified, so as to agree closely with Mendel’s expectations” [Fisher, 19361, whereas the interpretation of his experiments is accepted as valid. During the past 20 years this statement caused Mendel to be widely accused of falsifying his data [Weiling, 19851 (Fig. 1). The following is an attempt to offer an answer corresponding as closely as possible to our present knowledge.
two dcughters [Weiling,1983~1. His birthplace Heinzendorf (Czech: HynEice) in the Kuhlandchen, was located in the border area of that small part of Silesia which remained with Austria after the Silesian wars (17401742, 1744, 1756-1763) fought between King F’rederick I1 of Russia and Empress Maria Theresia of Austria. Thus, in practically all later official documents, Mendel was referred to as a Silesian (Sil.: Silesius). Ecclesiastically, Heinzendorf belonged to the Moravian parish of Gross-Petersdorf (6s: Vrazne) located about a half hour away. Its parish priest, Johann A.E. Schreiber (1769-18501, had a special interest in natural history and was known as an expert fruit grower; he had a lasting influence on the boy Mendel’s development [Weiling, 1984el. It was Schreiber, more than anyone else, who recognized the gifts of the young Johannes and persuaded his parents to release their only son for higher education in spite of their constrained financial situation. Initially Mendel attended the village school in Heinzendorf. At the age of 11 (1833) he transferred into the third grade of the Piarist Central School in Leipnik (Cs: Lipnik) and in the following year he was sent to the Gymnasium in Troppau (Opava) where he completed all 6 years successfully. At that time the Austrian school system provided in the public gymnasia four grammar classes followed by MENDEL’S LIFE two classes in the humanities always taught by the same Johannes (his birthname) Mendel was born on July 20 grammar and humanities instructor over the entire or 22,1822, the only son of peasant farmers who also had 6-year cycle. This teacher taught all subjects (Latin,
Fig. 1. The “Rogues’gallery” of Wade [Wade, 19831 including Johann Gregor Mendel.
Mendel Greek, geography, history, and mathematics) for 18 hours per week; 2 hours per week were devoted to mathematics [Timp, 19681. The prefect at that time, who also functioned as religion in$ructor, was an Augustinian Father of the Altbriinn (Cs: Stare Brno) chapter [Weiling, 1984al. At that time natural history was not a didactic subject in the school system. However, Mendel had the opportunity to regularly visit the Museum of Natural History of the school (today Schlesisches Landesmuseum) (cs: Slezske Muzeum Opava) which had been founded in 1822. There he was, presumably, of great assistance to its director and co-founder (also grammar teacher) Professor Faustin Ens (1782-1858), in caring for and developing the collections [Weiling, 1983al. The support which the parents were able to offer their son was restricted to regular “care packages.” However, these stopped when Mendel’s father became incapacitated after a severe accident and finally had to turn the running of his property over to his son-in-law. In his Autobiography [Mendel,18501Mendel wrote that “after several disasters following in rapid succession. . . his parents became completely unable to pay for the necessary expenses of [his] studies” (Fig. 2). Mendel tried to stave off his direst needs by offering remedial tutoring for which he had been approved through a special examination after a private course. Nevertheless, his constant deprivations led to a severe illness which forced him t o rest in his parents’ home from Pentecost till September in 1839 [Iltis, 19241. Mendel’s miserable existence did not improve after completion of his gymnasium studies in the middle of 1840and matriculation into the 2-year course of philoso-
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phy at the Philosophical Institute of the University of Olmutz (Olomouc). This course of studies included philosophy, Latin and Greek philology, mathematics, physics, religion, as well as the facultative fields of natural history and history. Greek, physics, and history were taught in the third and fourth semesters. As a stranger in town Mendel found no opportunity of supporting himself through remedial instruction [Mendel, 18501. He became ill during the final exams of the first semester, after having passed the examinations in mathematics and Latin philology with highest grades (Fig. 3). Thus, Mendel lost not only credit for the entire year, but also the free time granted to him till then for his studies. The spring and summer of 1841were apparently spent recuperating in his parent’s home, according to his Autobiography, even “a full year.” It was only when his younger sister Theresia offered him a portion of her inheritance that he was able to renew his studies in 1842 [Weiling, 19881, now as a paying student. “Using all of his strength he succeeded this time t o complete his two years of study” [Iltis, 1924, Mendel, 18501. He attained the highest grade in all courses (e = eminens) except for theoretical and practical philosophy, in which he got the second-best grade (1=prima classis). Thus, it appears that the practical courses, especially mathematics and physics, had a much greater interest for Mendel than a more speculative field such as philosophy, a conclusion supported by the qualifiers used to describe his efforts (“by application”) (Fig. 3). In this connection it is important to note that of the 20 or so hours of classes attended per week in Olmutz, 7 and 8, respectively, were devoted to mathematics in the first year and t o physics in the second both were areas of
Fig. 2. Final portion of Mendel’s handwritten account of his life [Mendel, 18501submitted by him to the Examination Commission of Vienna together with other documents.
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Fig. 3. Excerpts of the records of studies of the Philosophical Institute of the University of Olmutz with the entries pertaining to Johann Mendel. A the year 1841;B: the years 1842 and 1843 (State Archive Olomouc, Czechoslovakia). During the earlier attempt Mendel had the number 49,during his subsequent course (as repeater) the number 42.
special importance to him in his later scientific career. Mendel’s mathematics instructor was Professor Johann F’ux (1785-1848) [Weiling, 1984fl (Fig. 4) who was widely known for his textbooks; his physics instructor was Professor Friedrich F’ranz (1796-1860) [Weiling, 1983b1, a Prqmonstratensian and later Abbot of Neureisch (Nova Ris6). Before his appointment in Olmiitz (1842), F’ranz had taught physics for 19 years a t the Philosophical Institute in Briinn, and during that time he had lived in the Altbriinn monastery of the Augustinians [Weiling, 1982al. Franz gave Mendel a solid character reference, in fact referred to him “as almost the best” in physics [Iltis, 19241.On his recommendation Mendel was accepted as a novice in the Altbriinn chap-
ter after completion of his philosophical studies (1843). This freed him at once of his struggle for existence and “courage and strength returned with that level of comfort desirable for all studies” [Mendel, 18501. In his Autobiography Mendel wrote that his condition decided on his change of status. This was not meant to refer to the priestly state, as has sometimes been assumed, but rather to the monastic state, i.e., membership in an order. In the contract (1842) in which Mendel’s father turned over his home and farm to his son-in-law,he also makes provision for his son Johann in case he were “to follow his wishes and enter the priestly state” and in case he would be “prevented through a disease” from “attaining the priestly state’’ [Iltis, 19241.
Mendel
i b c r
Irit@tuetiP nab aiebctc %leebra.
--#wwwwMSImQe, 1839. ;Drub u n b ‘ p a p t t r @ o n 2ldlIol6 e r a r n i b f .
Fig. 4. The textbook of Arithmetic and Basic Algebra from the series on pure mathematics by Johann Fux, Olmutz, 1839.
After completion of his novitiate, Mendel absolved his theological studies between 1844 and 1848 at the Episcopal Seminary in Briinn. On August 6, 1847 he was ordained a priest. During the course of his studies he also completed a l-year (1845-1846) agricultural curriculum (Fig. 5) at the Philosophical Institute in Briinn under Professor Franz Diebl (1770-1859). At the same time he attended a semester course on fruit growing and viniculture (Fig. 6). At the beginning of the 19th century (however,not at Mendel‘s time anymore) these additional studies were required of theology students, since the Austrian government intended the rural priesthood to effectively teach and pass on their agricultural knowledge to the local population. These studies were also in the best interest of the Altbriinn monastery with its own agricultural domains, and thus of its Abbot, Franz Cyril1 Napp (1792-1867) [Weiling, 1968, 1971bl (Fig. 7). After a brilliant performance in his professional examinations of the theological Faculty of the University
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of Vienna, Napp was appointed Professor of old-testamentary hermeneutics and ancient Oriental languages (including Arabic, Syriac, and Chaldean) at the Theological Institute in Briinn. In 1824 Napp has been elected Abbot and quickly mastered the administrative1 economic duties of the monastery. He was a member of the Executive Committee of the Moravian-Silesian Agricultural Society; Director of the Pomological Society (as of 1827),the predecessor of the later section for fruit, horticulture, and viniculture of the Agriculture Society; and, as of 1849, Vice-Director,and in 1865 the General Director of the Agricultural Society. As such, Napp manifested not only profound technical knowledge and interests, but also proved himself to be a skillful judge of people and a splendid organizer. And as the Director of the State Gymnasia of Moravia and Silesia he was for many years the supervisor of higher education until the reorganization of the Austrian school system after the revolution of 1848. Not only Napp, but also other members of the chapter held public office. Thus, the chapter had to provide the professors of philosophy and mathematics at the Philosophical Institute in Briinn and to keep appropriate candidates ready for these positions at all times [Weiling, 1982al. Even for the chair of Natural History and Agronomy the monastery was prepared to provide a trained candidate after the vacancy of 1825-1828 [Weiling, 19761. It is t o be expected that the theology student Gregor Mendel was in constant contact with these obligations of the chapter, particularly since he himself additionally completed the entire agriculture curriculum then available. In his Autobiography he emphasized that during his theological studies he had dealt with botanical and natural-historical problems in the framework of the available opportunities and that, as a consequence, his liking for natural history increased greatly. With great likelihood Mendel was also confronted during these years with questions of heredity, i.e., the question of how, according to which rules, above all valuable traits are transmitted from generation to generation, and how crossing of sorts and types could combine and increase valuable traits. Astonishing results of some sheep breeders in the Briinn area had regularly occasioned detailed discussion of these problems in the 1820s and 1830s at the meetings of the Agricultural Society; even at the beginning of the 1840s they were a subject at an international scientific meeting at which Napp participated substantially in the discussion [Weiling, 19881. Botanically, the problem of plant improvement through crossing, especially in fruit growing, was of special interest. But also the efforts in collecting extensive assortments of different types, e.g., in sheep breeding (wool improvement) and in viniculture (Fig. 8), pointed in this direction and may have been ofinterest to the young Mendel. Soon after completion of his theological training the young Mendel turned out to be little fit for practical pastoral duties. According to a report by Napp to the Bishop of Briinn “at the bedside of the ill and suffering [Mendell was overcome with a paralyzing shyness, and he himself then became dangerously ill” [Iltis, 19241.
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Fig. 5. “Report card” concerning the outstandingly successful performance by Mendel during the second semester of the study of agriculture at the Episcopal Philosophical Institute of Briinn. The certificate is signed not only by the instructor Professor Diebl, but additionally by the certifying commissioners of the Bishop and of the Moravian Silesian Agricultural Society.
Therefore he was freed up for teaching and in September 1849 he was appointed adjunct instructor at the Gymnasium in Znaim (Znojmo)where he taught Latin, Greek, German, and mathematics during the winter semester [Kfiienecky, 1965; Czihak, 19841. However, since he lacked the required state qualifications to teach, at the urging of the Director of the School after
this semester he applied to the appropriate agency in Vienna to take the examination in Natural History for all grades, but in physics only for the lower grades. Mendel did not pass this examination; however, the notification, dated October 17, 1850, was not forwarded to him till August 1851 [Weiling, 19861. At the advice of Professor Andreas von Baumgartner (1793-1865) (Fig.
Mendel
t. f. ')lroiqTor bcr P~nbmirtl)id)~ft6kf)reunb aUjemcintn %JtUrl 8ef4iete Jn Err pl)ilofop$ifd)en EtlpnPdlt iu Brdiin unb Binit0 glirte mef)rrrer IunEloirt~f@JftlidW@efCuid)aften 3nns
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Fig. 7. Prelate Franz Cyril1 Napp in contemporary clerical garb.
unb %u6lanbe&
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---
- ----=-==zT;;&-- _ _
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SrCitut 1644, Bcbrudt bei %ubolp$ %ol)rer'4 f d Bittior. Fig. 6. Professor Diebl's textbook of arboriculture, especially pertaining to fruit trees, viniculture, and forestry, Briinn, 1844.
9) who had been the examiner in physics but in the meantime had been appointed the Austrian Minister of Commerce, Mendel enrolled as a special student for further studies a t the University of Vienna. During the reorganization of higher studies in Austria after the revolution of 1848 the philosophical institutes had been dissolved; they existed only in locations where there was also a seminary since theological training had t o be preceded by attendance a t a philosophical institute. The natural-historical subjects of these institutions were transferred to the gymnasia whose curriculum was thereby expanded by the 7th and 8th grades. In order to meet the need for appropriately trained instruc-
tors, chairs were created or reorganized, primarily within the philosophical faculty of the University of Vienna, in order to offer required courses in physics, botany, zoology, and chemistry [Weiling, 19861. Thus, in Vienna a new Physics Institute was created under the direction of Professor Christian Doppler (1803-1853) (Fig. 10); it began instruction late in the winter semester 1851-1852 in a recently completed and newly equipped institute building. We are particularly well-informed on the operations of this institute because it was based on regulations which had been formulated by the Ministry on the basis of a draft requested by Doppler. Accordingly, the maximally three semester-long training courses in physics consisted of 2 hours per day of active classroom instruction, with the entire rest of the day devoted to individual demonstrations or research projects. In this connection each of the candidates, after completing the work and experiments required for school instruction, was to perform an individually assigned project. These projects were to include the appropriate library research, the experimental design and protocol, as well as a final report under continuous supervision and eventual evaluation and correction by the Director of the Institute. In addition, these research papers were to be submitted to the Ministry at the end of academic year together with the Director's progress report [Weiling, 19861. Mendel began his studies in Vienna late, 4 weeks after the beginning of the semester, however, in time for the
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Fig. 8. List of the type of grapes grown close to the chapter of St. Thomas, Altbriinn [Mittheilungen, 1868, No. 21, May 1830, pp 166-1671. During the first half of the 19th century there were similar collections of grapes in two other places in Brunn.
opening of the Physics Institute. As a special student (ausserordentlicher Eleve) he attended exclusively the Physics Institute during the first semester and part of the interval between semesters. It may have helped Mendel that, like Mendel, the Assistant a t the Institute, Franz Pekarek, who held this position over the next several years, had also been active as an adjunct instructor during the winter semester 184911850 at the Gymnasium in Znaim. Only during his second semester did Mendel take additional courses: plant morphology and systematics in botany under Eduard Fenzl (1808-1879) (Fig. 91, and systematics and lab in zoology under Rudolf Kner (1810-1869). However, there were some scheduling
conflicts with physics. During the third semester it was not possible for Mendel t o attend the lectures announced by Doppler who became ill and died shortly afterwards (1853). Doppler was immediately replaced by Professor Andreas von Ettingshausen (1796-1878) (Fig. 9) under whose direction the practical projects at the Physics Institute remained considerably restricted during the first few years. During this semester Mendel took most of his non-physical courses: under F'ranz Unger (18001870) (Fig. 9)anatomy and physiology of plants as well as the first lab course at the University of Vienna in botanical microscopy; under Josef Redtenbacher (18101870) (Fig. 9) general and pharmaceutical chemistry as well as methods of chemical analysis. In addition he
Mendel
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Fig. 9. Group portrait of the members of the mathematical-historical class of the Academy of Sciences in Vienna (about 1855)[Meister, 1947, plate 19, with five of Mendel’s teachers A.v. Baumgartner (second sitting from left), A.v. Ettingshausen (first sitting from left), E. Fenzl (fifth standing from left), F. Unger (first standing from right), J. Fkdtenbacher (fourth standing from left).
attended two 1-hour lectures on paleontology as well as a 1-hour lecture on logarithmic-trigonometric tables. During his fourth and last semester Mendel took von Ettingshausen’s course on introduction to and use of physical instruments and higher mathematical physics, and Redtenbacher’s course on organic chemistry. In addition, he established connection, perhaps as early as the second semester, with the zoological division of the Court Natural History Collection and its director Vinzenz Kollar (1797-1860). This resulted in a paper which Mendel presented on July 21,1853, a few weeks before his final return to Brunn, before the ZoologicalBotanical Society of Vienna [Mendel, 1853; Weiling, 19861. Thus, Mendel’s studies in Vienna were primarily devoted to physics, having worked completely or extensively at least 1full year in the Physics Institute under Doppler. Doppler died early, but here Mendel may have acquired his later so successfully applied scientific method, especially since it can be assumed that during the first year of the newly created Institute Doppler proceeded strictly according t o the rules of the Institute, largely due to his own initiative. In addition, Doppler was far more practically oriented, and didactical in his mode of work, than his successor von Ettingshausen. Since the rules of the Physics Institute contain detailed instructions to study the literature and since it can be assumed that Mendel personally acquired at the latest during his stay in .Vienna C. F’r. von Gartner’s (1772-1850) book: “Uber die Bastarderzeugung i m PfZanzenreich” (concerning the production of hybrids in the plant kingdom, 1849; Figs. 11, 12); it can be concluded that under the influence of that book Mendel read the paper he later quoted by J. G. Kolreuter
(1733-1806) [Kolreuter, 1761-17661, W. Herbert (1778-1847) [Herbert, 18371,and H. Lecoq (1802-1871) [Lecoq, 18451, probably accessible only in Vienna. We can therefore assume that Mendel made the detailed plans for his later Pisum experiments in Vienna, and began them, i.e. obtained and tested the various types and sorts of seeds, immediately after his return to Brunn. However, upon return t o Brunn (18531, Mendel did not, as might have been expected,present himself for the final exam, but only 3 years later when difficulties arose in the as yet incomplete Oberrealschule in Brunn where he taught without having taken the exam. Mendel did not pass this exam either. According to Kfiienecky [19631 a t the beginning of the written exam on May 5, 1856in Vienna, Mendel became so ill that he was unable to write and gave up. It is known that Mendel was in poor health while preparing for the exam presumably through overexertion. Now he became so ill that, in spite of difficult travel conditions, his father and uncle rushed over 120 km from Heinzendorf to support him [KEiienecky, 19651. Thereafter Mendel did not attempt to repeat the exam, and the Director of the Oberrealschule, Josef Auspitz (1812-1889) was evidently able, on the basis of Mendel’s exceptional pedagogic performance and in the face of the official rules, to retain him as a professor at the school (Fig. 13). Mendel informed the Munich botanist Carl Nageli (1817-1891) on April 18, 1867 that he had performed the actual experiments of his Pisum work from 1856 until 1863, inclusively [Correns, 19051. In contrast to Fisher 119361 (who later corrected himself) [Fisher, 19551and in agreement with Orel [Orel, 1971al it may be assumed that the first crosses were performed in
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Fig. 11. Carl Friedrich von Gartner [Stubbe, 1965, p 1021.
netic study on differences in flowering time) intended for publication were concluded in 1863 to obtain “space and time for the cultivation of other experimental plants” [Correns, 19051. At that time infestation with the pea beetle Bruchuspisi was so heavy that beginning in 1864 substantial damage was recorded and in 1865 barely 20-25% of harvested peas were uninvolved. He mentions in the same letter that in the vicinity of Brunn the cultivation of peas had to cease altogether. The final analysis of his experiments and the preparation of the manuscript probably occurred in 1864. MenFig. 10. Bust of Christian Doppler in the courtyard of the Univer- del reported on his work in detail t o the Naturforschende sity of Vienna. Verein of Brunn (founded in 1861) a t the sessions of February 8, and March 8, 1865. Mendel’s paper was printed in the volume of Proceedings for the year 1865; however, it appeared only toward the end of 1866 (Fig. 1856. This would involve at least the 118 crosses per- 15).The reason for this delay was the war of 1866 [Weilformed on 25 pea plants, with the traits smooth and ing, 1970~1, which visited on Brunn a temporary occupawrinkled seeds respective green and yellow seed color, tion by Russian troops, food shortages, and a serious during the year of his disastrous second board examina- cholera epidemic with some 3,000 deaths (1,000 citizens tion. In the two preceding years he had subjected 34 and more than 2,000 Prussians) [Mendel, 18663. Accord“more or less different” types of peas to a test of purity, ing to the information on its yellow covers, this volume and selected 22 types for his subsequent experiments appeared in an edition of 500 copies of which 115 went to [Mendel, 1865a,bl. scientific institutes or libraries [Weiling, 1969133.There In order to appreciate his work during the years of his were 40 reprints of Mendel’s work; the whereabouts of 13 Pisum experiments it must be mentioned that by no of these is presently known [Weiling, 1984~1. means all experiments entered his later publication and Already 6 months after its appearance Mendel’s work that since 1854 he also worked at the Brunn Ober- was cited in the May 14, 1867 issue of the well-known realschule teaching the two lowest classes of Naturlehre botanical journal Flora in a “repertoire of the periodic (Physics) and natural history with, depending on the botanical literature.” In addition, Mendel’s work is number of parallel classes, 18 and 27 hours per week of quoted both in the register of authors as well as in the instruction and 60 to 120 students per class [Programme index of subjects (key words: Bastarde and Hybridittit) of of the Oberrealschule Brunn] (Fig. 14). the volume of this journal [Weiling, 1969133.By 1870one According t o Mendel’s own information (second letter other publication, by 1880 another four, by 1890 a furto Professor-Nageli) all experiments (except for one ge- ther two, and one other by 1900 in the German, Swedish,
Mendel
Fig. 12. Mendel’s personal copy of the book by Gartner. It contains numerous annotations and notes in Mendel’s handwriting, especially on the front fly leaves.
Russian, and Anglo-Americanliterature had cited Mendel’s Pisum work [Weiling, 1971al. A particularly thorough discussion is in the 1874 St. Petersburg dissertation of Johannes Schmalhausen, a descendant of a family originally from Bremen [Weiling, 1966, 1974, unpublished manuscript]. The formerly frequently voiced opinion that Mendel’s work was unknown before 1900 and thus had fallen into oblivion is untenable on the basis of these data. However, the problem of the genetic process itself and its laws lost importance in Brunn because of the increasing cotton industry and simultaneous reduction of the importance of sheep wool. On the other hand, work in cytology, especially by Walther Flemming (1843-1905) a.o., August Weismann (1834-19141, and Eduard Strasburger (1844-1912), yielded detailed knowledge
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on cell division and the behavior of the easily stainable bodies in the nucleus (chromosomes)which appeared to have something to do with the genetic mechanism. The British genius, Sir Francis Galton (1822-19111, who worked extensively with the heredity of human faculties and character traits and developed his own model of heredity, apparently was unacquainted with Mendel’s work. Following the strong recommendation of the influential Munich botanist Carl Nageli, Mendel was induced to begin detailed crosses in Hieracium. However, through behavior which is peculiar to this plant (apogamy) and which was recognized and worked out only much later, the reproductive mechanism functions in a totally deviant manner. New and completely different challenges which Mendel had to meet as of 1868 did not allow him the required time for further systematic genetic investigations. Nevertheless, the Hieracium experiments, presented by Mendel before the Naturforschende Verein in Brunn on June 9, 1869, are remarkable [Mendel, 18691. Hieracium was a difficult genetic subject because of the delicate construction of the individual blossoms; however, the fact that with only one exception all known artificially produced Hieraciurn hybrids derive from these experiments of Mendel attest to his extraordinary experimental skill. From five of six successful hybrids Mendel sent living material including the parental stock to Nageli in Munich. It was propagated in the Munich botanical garden and then was incorporated into the subsequent systematic investigations of Nageli and his coworker Albert Peter (18531937) [Peter, 1884,1885; Nageli and Peter, 18851.Peter included specimens of 11 original forms and 17 hybrid from Mendel’s stock in his four volume herbarium of the Hieraciae [Peter, 1885, 18861 (Fig. 16). Of this work, I was able to track down 26 admittedly in part incomplete specimens in herbaria of 13 different European countries [Weiling, 1969al. On March 31,1868 Mendel was elected the successor of the deceased Abbot Franz Cyril1Napp of the Altbrunn chapter. This brought to an end not only his work as adjunct Professor in the Oberrealschule, but also, after a short phase-out period, the complete cessation of his work in genetics. Administrative and public service obligations predominated, especially in the executive committee of the Moravian-Silesian Agricultural Society. In 1874, a tax law was enacted which obligated monasteries and convents to substantial contributions to the Religious fund from which the State drew means to support the church. Mendel’s protest grew into a protracted and wearisome confrontation. Since he viewed the law as unjust, Mendel, as the only prelate in the Austrian empire, resisted it, in the face of the ensuring confiscation of a substantial portion of the monastery income. After Mendel’s death, his successor compromised; however, he insisted, successfully, on return of the overpayments. At the same time the chapter was relieved of any further payments of this tax, since the true income of the monastery was below the level stipulated by the law. Early in the morning of Epiphany (January 6,1884)
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Weiling
Fig. 13. A previously little known (incomplete) group portrait of members of the Altbrunn chapter of St. Thomas from a time between 1861-1864 (University Library Brno, Czechoslovakia). This is a different grouping than that in Iltis [1924,plate 41 involving the same persons and taken at the same occasion.Ofthe persons portrayed here, the following were engaged as teachers: Mendel holding a fuchsia blossom; Fr. Thomas Bratranek (standing third from left), for 30 years Professor ofGerman Literature at the University of Krakau, today Krakow, Poland: Fr. Antonin Alt (standing, second from right): elementary mathematics, at times director of the Gymnasium of Troppau (Opava, Czechoslovakia); Fr. Benedikt Fogler (standing, first from the left), instructor of German, Italian, and French at the Oberrealschule in Brunn; Fr. Paul KfiikowskJi (standing second from left), composer, director of the Thurn-Foundation for Musical Education (conservatory) at the Altbrunn chapter (later attended by the famous Moravian composer LeoB JanaEek, 1854-19281, as well as choir director of the Cathedral of Olmutz (Olomouc).
Mendel died of chronic renal disease and heart failure His failure during the first board examination must (Bright’s disease and dropsy according to the death cer- also be regarded as a blow of fate. He had to fail, because tificate) [Kfifenecky, 1965; Weiling, 1984dl. without appropriate specialty training, he had to subject himself t o much higher standards of examination MENDEL’S PERSONALITY which had been improved during the reorganization of Mendel was a multifaceted personality whose life was higher education following the 1848 revolution. marked not only by remarkable successes but also by As a further blow of fate must be regarded the failure great adversities and blows of fate. The severe accident of his second board examination in 1856 which he had to and incapacitation of his father (1838)and other misfor- call off at the very beginning because of severe illness tunes in his family deprived him of financial support for with inability to write with subsequent irregular aphis education. The associated deprivations damaged his pointment as supplementary professor. Apparently his health through inadequate nutrition, illnesses, and re- physical and emotional status had been so badly imduced resistance. This forced him to interrupt his philos- paired by the preceding misfortunes that he was not up ophy studies already during the first semester exams to the additional stress of preparing for and taking the causing him to loose his free study time. He was able to examination. A final blow of fate was the prolonged and wearisome, continue his education only after his sister Theresia gave him a part of her inheritance which allowed him to health-damaging conflict with the government about complete his philosophical studies to take advantage of the religious tax which Mendel, in fidelity to his oath of the subsequent opportunity to pursue a priestly voca- office and his conviction about the illegality of the law, tion as a monk in the Altbriinn Chapter. Mendel believed unable to avoid. thanked his sister by financing the education of her This externally evident professional failure of Mendel three sons, one of whom died during his studies. must be contrasted with the fact that it was his Pisum
Mendel
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