by John Hulme
"Versuche uber Pflanzenhybriden" [see footnote] (“Experiments with Plant Hybrids"), he said quietly in German, the language of science in the Austrian Empire.
"Good, excellent," said Theimer enthusiastically, "plant hybrids. Brother Gregory."
Few of warmly coated men sitting in the Realschule that February evening could have imagined the significance of what they were about to hear, least of all Brother Timothy. He sat beside Abbot Napp in the front row of seats and kept his long fingers uncomfortably twisted on his lap. Behind him, Brother Matthew stared at the long hair and longed to grab a handful and pull. For he knew better than most that Brother Timothy was an ambitious fanatic who would stop at nothing to achieve his goals. There were only two things important to Brother Timothy; the Word of God and the future of Brother Timothy.
Since coming to the Augustinian Monastery in 1834, the ambitious monk had made a very careful study of his fellow clerics, and then had begun his climb towards the abbacy. Like Mendel he had attended Olomouc Philosophy Institute and had been given the opportunity to study at Vienna University by Abbot Napp, the man he hoped to replace one day. Brother Matthew ground his teeth as he remembered the day Brother Timothy returned to the monastery. In that year Klacel had gained a friend and also had become Brother Timothy's first victim. By devious means, including leaking Klacel's private papers to the local authorities, Brother Timothy had arranged for Brother Matthew to be dismissed from his teaching post, and had promptly taken it over for himself. From 1843 to 1851, Brother Timothy had taught philosophy in Brno in place of Klacel.
With Klacel out of the way, the ambitious monk had soon identified Brother Gregory as the next obstacle to be removed. Not that Brother Gregory knew or understood his role as appointed victim. Mendel was quietly popular among the Brothers at the Monastery. He served the Lord and his garden equally, but never made a fuss or even lost his temper when one of the local boys picked his experimental peas for dinner one evening, ruining almost a year's work. He was good at paper work, and even better at resolving the various disputes that occasionally erupted among the Brothers; religious or secular. But his love (after God) was science. As Brother Timothy knew only too well, Mendel had a good background in the subject, having studied with F. Diebl in the Brno Philosophical Institute, and F. Unger at the University of Vienna. Diebl had published a four volume book on plant breeding which had been required reading during Mendel's time there in 1846.
This important book described how wild plants could be tamed and cultivated into improved forms by artificial pollination. It also described techniques for crossing one plant with another, blossom anatomy, and, after pollination, how to collect the seeds; all topics which were to be critical in Mendel's own work.
Not knowing the what was going on in the minds of at least some of his audience, Mendel moved to the front of the room and cleared his throat. Sitting liked a cat watching a mouse, Brother Timothy listened as Mendel began to describe what he had done.
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Chapter Six
Opening Remarks
"Experience of artificial fertilization," Mendel began, looking owlishly through his glasses, "such as is effected with ornamental plants in order to obtain new variations in color, has led to the experiments which will here be discussed." He paused, coughed and continued in soft German, "The striking regularity with which the same hybrid forms always reappeared whenever fertilization took place between the same species induced further experiments to be undertaken, the object of which was to follow up the developments of the hybrids in their progeny."
"To this object numerous careful observers, such as Kolreuter, Gartner, Herbert, Lecoq, Wichura [see footnote] and others, have devoted a part of their lives with inexhaustible perseverance."
Which is more than I have, thought Brother Timothy, and tuned out the next pedantic sentences, thinking instead of how easy it had been to manipulate the gullible Mendel. After his book, The Anatomy and Esthetics of Plants had been published in 1853, he has signed a copy and presented it to Mendel personally. Delighted at the attention, Mendel had reciprocated and allowed Brother Timothy to examine his own data on plant hybridization.
Their seemingly cordial relationship had been interrupted briefly when Brother Timothy had taken a post as research assistant to Professor Hanus in Lemberg University, but had picked up again after his recent return to the monastery. It had not been hard to get Mendel to propose him as a member of the new Natural History society and become an elected member in 1863. Everyone in the monastery knew that he was a particular favorite of Abbot Napp, who considered him an outstanding scientist. Many already considered him the leading contender for Napp's abbacy a delightful train of thought lasted long enough for Mendel to reach the next part of his presentation.
"The value and utility of any experiment is determined by the fitness of the material [see footnote] to the purpose for which it is used, and thus in the case before us it cannot be immaterial what plants are subjected to experiment and in what manner such experiment is conducted." For the first time, Mendel looked up from his notes and glanced at his audience. Makytta and Brother Matthew were still listening attentively, but Grunewald's eyes were already beginning to glaze over. At least nobody was asleep yet.
He continued, "The selection of the plant group which shall serve for experiments of this kind must be made with all possible care if it be desired to avoid from the outset every risk of questionable results."
"The experimental plants must necessarily:
“(1) Possess constant differentiating characteristics.
“(2) The hybrids of such plants must, during the flowering period, be protected from the influence of all foreign pollen, or be easily capable of such protection.
"The hybrids and their offspring should suffer no marked disturbance in their fertility in the successive generations." And so it went.
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Chapter Seven
Interruption
"At the very outset," he said firmly, "special attention was devoted to the Leguminosae on account of their peculiar floral structure [see footnote]. Experiments which were made with several members of this family led to the result that the genus Pisum was found to possess the necessary qualifications."
At this, Brother Timothy pricked up his ears and allowed himself and internal smile; the only kind he allowed himself. When Mendel had returned from his short University experience, he had brought with him the beginnings of an idea concerning the mechanism of heredity and had asked Klacel and others about the best possible research material with which to test out his ideas. Remembering problems that he had encountered while trying to work with the genus Hieracium, Brother Timothy had slyly suggested to the enthusiastic monk that he try forming hybrids with these plants, knowing full well the difficulties and delays he would encounter.
Others in the Monastery had proposed experiments using mice, but the Abbot had vetoed the idea as being too close to idolatry and blasphemy against God. Plants were safe, and the common pea plant, which was Napp's choice, had no religious constituency. Eventually Mendel had diplomatically agreed with his Abbot and began his experiments using the common garden pea, but not before Brother Timothy had delayed him for a year or two.
"In all," said Mendel, "34 more or less distinct varieties of peas were obtained from several seedsmen and subjected to a two year's trial. In the case of one variety there were noticed, among a larger number of plants all alike, a few forms which were markedly different. These, however, did not vary in the following year, and agreed entirely with another variety obtained from the same seedsman; the seeds were therefore doubtless merely accidentally mixed." If he had expected sympathy at this result, he did not get it, so he continued, "All the other varieties yielded perfectly constant and similar offspring; at any rate, no essential difference was observed during two trial years." A smile
, "For fertilization [see footnote] 22 of these were selected and cultivated during the whole period of the experiments. They remained constant without any exception." - a key point that he wanted to emphasize. One of the reasons he felt that he had been successful [see footnote], was the fact that the starting material for his experiments were some how "pure" and gave constant varieties of offspring during his hybridizations.
"Brother Gregory," interrupted Brother Timothy, smoothly between sentences. "To what species did this pea plants belong? Would that not be critical to your work?" It was rare for a presentation to be disturbed in this way, but Brother Timothy had prepared his own ground very carefully and knew that this point was the first weakness in Mendel's paper. In the seat next to him, he felt Abbot Napp stir, but he didn't take his eyes off Mendel. This was a critical moment. If the presenter hesitated, he knew he would have scored his first small victory, and also broken the monk's rhythm.
But Mendel, after getting over the shock of having his talk interrupted, simply shuffled some of his notes, and replied, "According to the opinion of experts, the majority of the plants I used, belong to the species Pisum sativum; while the rest are regarded and classed, some as sub-species of P. sativum, and some as independent species, such as P. quadratum, P. saccharatum, and P. umbellatum." He paused, adjusted his round glasses and stared over them directly at Brother Timothy. "The positions, however, which may be assigned to them in a classificatory system [see footnote] are quite immaterial for the purposes of the experiments in question. It has so far been found to be just as impossible to draw a sharp line between the hybrids of species and varieties as between species and varieties themselves."
A barely suppressed chuckle ran around the room, starting with snort of delight from Brother Matthew. It was not unusual for spirited debate to spring up between scientific antagonists, as the holders of one opinion tried to discredit the opinions of a contrary position. Most of the time, however, debating points were scored by those who either posed an impossible question, while making it seem eminently reasonable, or by those who could answer an impossible question with a straight face and without loosing their dignity. Loss of face was is only defeat that matters in science, a fact most professional practitioners recognize. It was good to see that Brother Gregory could give as well as he got. Rubbing their hands, not entirely to get them warm again, the audience settled down. Perhaps this talk was going to be better than expected.
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Chapter Eight
The Data
Capitalizing on his small victory, Mendel came at once to the heart of his thesis, "If two plants which differ constantly in one or several characters be crossed, numerous experiments have demonstrated that the common characters are transmitted unchanged to the hybrids and their progeny." Consistency, thought Mendel, the transmitting element [see footnote] is constant, not a fluid. Unger, his mentor at the University of Vienna, would be very interested in this result, he had frequently stated in his lectures that the transmission mechanism [see footnote] was unknown, although he has once written, "embryo formation is determined by both sides (i.e. both parents) and represents the middle way. The middle forms are a mixture of characters."
Continuing, "But each pair of differentiating characters [see footnote], on the other hand, unite in the hybrid to form a new character, which in the progeny of the hybrid is usually variable. The object of the experiment was to observe these variations in the case of each pair of differentiating characters, and to deduce the law according to which they appear in successive generations. The experiment resolves itself therefore into just as many separate experiments as there are constantly differentiating characters presented in the experimental plants."
This was the key, each parent donated a transmission element to the hybrid. These elements combined in the hybrid to produce a new character, and in subsequent progeny from these hybrids, the original characters sorted themselves out according to laws, which Mendel felt he had untangled.
Had Mendel been a more effective presenter, he would have paused dramatically at this point, and then rammed home the significance of his findings. Brother Timothy held his breath. An effective communicator himself, he recognized that Mendel had reached a critical point in his paper. He need not have worried. In that cold, Realschule auditorium, Mendel, the discoverer of a new branch of biological science, turned the page of his notes, continued his talk in the only way he knew, and vanished from the pages of science history for 30 years.
"Each two of the differentiating characters enumerated above were united by cross-fertilization [see footnote]," he said, and because he never made an unsubstantiated statement, he went on, "There were made for the
1st trial 60 fertilizations on 15 plants.
2nd trial 58 fertilizations on 10 plants.
3rd trial 35 fertilizations on 10 plants.
4th trial 40 fertilizations on 10 plants.
5th trial 23 fertilizations on 5 plants.
6th trial 34 fertilizations on 10 plants.
7th trial 37 fertilizations on 10 plants.
"The plants were grown in garden beds, a few also in pots, and were
maintained in their natural upright position by means of sticks, branches of trees, and strings stretched between. For each experiment a number of pot plants were placed during the blooming period in a greenhouse, to serve as control plants [see footnote] for the main experiment ..."
The data and the details droned on and on. Even his friends from the monastery and his old schoolteacher, try as they might, lost interest as Mendel explained every tiny aspect of pea plant growth and differentiation. Even the upright Germans began to slump in their chairs, and the less patient Grunewald took out another cigar and pointedly lit it. This was not what he had come to hear.
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Chapter Nine
Help from the Teacher
Eventually Mendel began to describe the various forms his hybrids took, but it was too late. When he finally came to the statement that has been a staple in all biology textbooks ever since, practically no one in the room grasped its importance, and Brother Timothy was the only person still having a good time.
"In this generation," Mendel continued, unaware that he had lost his audience, "there reappear, together with the dominant characters, also the recessive ones with their peculiarities fully developed, and this occurs in the definitely expressed average proportion of 3:1 [see footnote] , so that among each 4 plants of this generation 3 display the dominant character and one the recessive. This relates without exception to all the characters which were investigated in the experiments."
Sensing that the small group of members was growing hostile, the school teacher from Heinzendorf tried to rescue his friend, "Brother Gregory, do you remember the work we did together with Father Schreiber using fruit trees? We often seemed to find hybrids that never looked like the parent plants. Didn't you find any pea plants that were a mixture of your characteristics?"
Mendel blinked. "Ahh," he said, and looked directly at Herr Makytta, "a good question, and vital to my thesis. All the characters that were investigated [see footnote] in these experiments; the angular wrinkled form of the seed, the green color of the albumen, the white color of the seed-coats ..." He went on to list all the various pea characteristics that he had investigated, concluding, "... and the dwarfed stem, all reappear in the numerical proportion I have given here, without any essential alteration." Then the important statement, "Transitional forms were not observed in any experiment." He made the point forcefully. It had been a critical discovery that characters did not 'blend' into one another like pots of paint.
All the naturalists in the room, at least those familiar with Diebl and Unger's work, were aware of the debate about inheritance. One school of thought was that children inherited a 'fluid’ [see footnote] (and some thought this fluid came exclus
ively from the father) in which there was a blend of characters such as the distinctive Habsburg nose, or Mendel's seed shape. This 'blend' determined the appearance of the offspring. If they had been listening that evening, they would have heard Mendel put the nail in that coffin. Characters do not blend during the inheritance process. Mendel had shown that characters such as the color of seed-coats are transmitted intact from parent to child, generation after generation. It was an important discovery.
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Chapter Ten
The Questions
But Mendel had forgotten Brother Timothy.
"Brother Gregory, did I hear you correctly when you said that it was not important where and when the seed pods developed on your plants? Do all the pods and all the seeds behave the same?" It was a vicious question. For several years Brother Timothy had been watching, waiting and reading Mendel's notes. In innocent seeming debate he had asked the honest Monk leading questions, and flattered by the interest, Mendel had occasionally admitted to some of his research problems. From these admissions, Brother Timothy felt he knew where the weaknesses lay in Brother Gregory's work. He was just starting to use that knowledge.
"Basically yes," admitted Mendel in a soft voice. It was barely noticeable, but he had hesitated before giving his answer. Also the response had been evasive, a common trait for speakers on soft ground. But the ever-alert Brother Timothy sensed where to go next.
"But is it not true that the order in which the pods form on your plants has an important role to play in the manner in which the seeds form?" Brother Timothy was relentless.
As if speaking from a long way away, Mendel replied, "In some few plants only a few seeds developed in the first formed pods, and these possessed exclusively one of the two characters, but in the subsequently developed pods the normal proportions were maintained nevertheless." Even he heard the weakness in the excuse, and several people in the audience coughed. Brother Matthew put his head in his hands and looked down at the floor.
