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Organ and tissue transplantation in animals

In the rare hours of leisure that he had after fulfilling the duties of a preparator, Paul Bert conducted experiments on the transplantation of various tissues. Separate reports about them appeared in the "Bulletin of the Scientific Society of the city of Nona"; Behr presented the results of these studies in full in the monograph "On Animal Transplant" (1863), which he dedicated to his teacher Pierre Gratiola.

By the time Beer's monograph was published, data on the transplantation of individual organs and tissues in animals and humans could be found in manuals on surgery and physiology. Behr was the first researcher to take the trouble to study and summarize the literature on organ and tissue transplantation. He devoted a special chapter to this question in his monograph.

The literature review in this chapter is striking in its thoroughness. “We can say with all responsibility,” Ber wrote, “that until recently the question of transplantation in animals has not been subjected to special study. Some experimenters viewed transplantation experiments as a method for testing ingeniously conceived constructions, others resorted to transplantation to elucidate some of the more intimate ones, sides of physiological functions, and most of this was done from a purely surgical interest "*. This was the most complete excursion into the history of the issue of tissue and organ transplantation for that time, which is of undoubted interest to this day. He convincingly shows how essential Paul Beer's contribution to the development of this important branch of experimental biology is.

*(Bert P. De la greffe animale. Paris, 1963, p. 7.)

The idea of ​​replacing sick or damaged organs and tissues of a person with healthy ones has long worried people. Already in Greek mythology, there are references to organ transplants from animals to humans. The painting by the monk artist Fra Angelico (Fra Giovanni da Fiesole, 1387 - 1455) captures the motif of an early Christian legend about the holy brothers Cosma and Damian, which tells of a successful human leg transplant. In ancient India, priests learned the secret of restoring a lost nose with the help of forehead skin, and the secret of the art of rhinoplasty was carefully guarded and was an important means of influencing ordinary people. In Europe, famous surgeons of the past, Celsus and Galien, knew and used nose repair.

History of surgery in the 15th century. tells about the successful outcomes of surgical transplants of various parts of the body (in particular, plastic surgery of the nose removed during punishment). It was then, outside the connection with the Indian priests, that the rhinoplasty method mastered with great skill was born - the so-called Italian method, when a skin flap with arms.

Perhaps the best known in this respect is the surgeon from Bologna Gaspar Tagliacozzi (16th century), who described in his monograph numerous successful operations on plastic surgery of the nose with skin flaps from the shoulder. Tagliacozzi even considered it possible to restore the shape of the nose with the help of the muscles of another person's face. True, later he abandoned this thought: "The exceptional character of the individual," he said, "excludes any attempts to carry out such an operation on another person. Since the strength and power of individuality is such that if someone is counting on his own capabilities in terms of improving" the union "(ie, engraftment. - L.S.) and moreover - obtaining minimal success, we consider him a superstitious person and poorly trained in physical sciences" *. With these figurative words back in the 16th century. Tagliacozzi pointed out the dangers awaiting a doctor who dared to cross the barrier of tissue incompatibility. However, the reconstruction of the human nose with the help of a skin flap of the upper limb (i.e., in modern terms, an option of autotransplantation) Tagliacozzi was extremely successful. This method has served the needs of practical surgery for about four centuries. A monument to Gaspar Tagliacozzi was erected in Bologna. The sculptor depicted a surgeon holding a nose in his hand.

*(Bert P. De la greffe animale, p. 7.)

Unfortunately, in that era, rhinoplasty did not become widespread in the surgery of a country like France. French doctors headed by the famous Ambroise Paré in every possible way excluded the Italian operation from the arsenal of remedies. For a long time, she even served as the subject of ridicule. Moreover, writers began to treat the issue of transplants ironically. Thus, Edmond Abu created the novel "The Notary's Nose", and the great Voltaire used in his "Philosophical Dictionary" a crude legend about how the transplant of the recipient's nose fell away with the death of the donor. The same legend was repeated by van Helmont in the story of a citizen of Brussels, who had a nose job done with the skin of a loader. Thirty months after the transplant, the graft was rejected, which also coincided with the death of the skin donor (the so-called "sympathetic nose").

In 1804, the Milanese surgeon Baronio reported on successful experiments in skin autotransplantation in sheep. Soon he was already talking about successful operations on skin grafting from one animal to another - intraspecific, and in some cases interspecific transplantation. Ten years later, the English surgeon Karpu, having familiarized himself with the achievements of Indian doctors, performed the first two successful rhinoplasty using a skin flap taken from adjacent areas, now this method, known in the literature as "Indian", began to spread rapidly in Germany and France. It was used in plastic surgery not only for the reconstruction of the nose, but also for the plastic surgery of the ears, lips, eyelids, and even non-healing fistulas. For the first time, surgeons appeared who did not limit their role to amputation, but create a new organ, often for cosmetic purposes. So, in 1823 Wünger restored a part of a woman's nose using the "free skin graft" method. The operation was successful. Hoffacker, a Heidelberg "duel surgeon" (so nicknamed for his frequent medical attention after duels), described 16 successful reconstructions of the nose, chin and other parts of the face that had been cut off with long rapiers.

By the time Paul Beer's work was published, some information had accumulated about transplants in animals and humans, often of a somewhat exotic nature. There were known individual works on the transplantation of hair, cockscombs, teeth, cases of engraftment in place of the skin, nose, ears, fingers, cheekbones, chins, sometimes partially isolated from the body for many hours. Attempts at intraperitoneal transplantation of testes, spleen, uterus, and stomach are described. Some expert testers even tried to transplant the periosteum, bones, muscles, etc. into the subcutaneous tissue.

It is easy to see that "transplantation in animals" (and in humans) in Beer's era was an operation to remove a fragment of living tissue from one animal and transfer it or to another place to the same or another animal in various versions. In a number of cases, these pieces of tissue turned out to be viable for quite a long time and to some extent continued their vital activity. Many of these experiments, often surprising or strange from the point of view of a modern transplantologist, have played a positive role in the study of certain physiological phenomena.

Behr had great respect for his predecessors such as Gunther, Puteau, Dieffenbach, Wiesman. He recognized the skill and boldness of their experiments, but noted that “they only opened the way without following it, and stopped at the first results they received. volume, penetrating into the problems that he opens, outlining the plan of upcoming experiments. In a word, no one has yet begun to comprehend the accumulated experience, this hunting area of ​​Pan, in the figurative expression of Bacon. The question of transplantation is still similar to a virgin. formula, all the achievements dispersed in separate compositions "*.

*(Bert P. De la greffe animale, p. eight.)

It is curious that to designate the transplantation of organs and tissues in animals, Ber, unlike his contemporaries, who used terms such as autoplasia, transplantation or "grafting", "welding", "adhesion", widely used the term "greffe" graft "). He used this botanical concept, the original meaning of which is "scion", "rootstock", in combination with the term "ammal", that is, belonging to an animal, "animal". From Beer's point of view, this terminology made it possible to characterize the studied phenomenon more broadly. It must be said that in a number of modern European languages ​​the botanical term "greffe" has taken root well and serves as a synonym for transplant in relation to animals and humans. The term introduced by Berm has become more capacious; now it means not only the transplantation process, but also the transplanted organ itself - the transplant.

Title page of the work of Paul Bera "Organ Transplant" - dissertation for the degree of Doctor of Medicine

Ber was the first of the researchers to try to analyze the types of transplants, combining them into two groups. He attributed two forms to the first:

a) a form of transplant, in which any part of the body is taken from one animal and transplanted to another, where it continues to live. This form is still used by transplantologists, who subdivide it into allotransplantation (transplantation from one animal to another within one species) and xeno-transplantation (transplantation of an organ or tissue of an animal of one species to an animal of another species);

b) a form in which two animals are connected to each other and are united by means of organic ties, directly merging and forming between themselves something like "life solidarity", in the words of Beer. He considered this form of transplantation to be analogous to transplantation used in botany. At present, advances in vascular surgery have made it possible to improve this form; however, cross circulation is not now accepted as a transplant option.

In the second group, Behr included such types of transplants in which some part of the body is first completely removed from the experimental object, and then, immediately or after some time, its connections with the body are restored. As an example of this form, he cites the engraftment of an amputated nose, fingers, etc. (replantation in modern terminology), plastic surgery (such as frontal rhinoplasty, which was mentioned above) and, finally, the use of distant parts of the body for plastic surgery (reconstruction of the nose using thigh skin).

Thus, in essence, Behr already distinguishes between auto-and allotransplantation, and in his classification he also provides for the possibility of replantation.In his dissertation, he even cites a clinical case of successful replantation of an incisor in a ten-year-old girl three hours later, ate an accident that caused a severe trauma to the face: he was knocked out the upper left large incisor, and the other three are dislocated and turned back. The knocked out tooth was found and, having provided first aid to the victim, they took her to a hospital located several kilometers from the scene. At the hospital, the surgeon carefully returned the three deflected incisors to their normal position and replanted the fourth, fixing the teeth with a special bandage. After two and a half years of the accident, the teeth were firmly implanted in the jaw in their normal position. It should be noted that Behr was extremely cautious in assessing the success in the field of transplantation, believing that in the issue of replantation, failures are somewhat hushed up and successful results are too high on the shield.

Behr set up many experiments on organ transplantation from one animal to another by the type of allotrans-plantacin. He tried to transplant feathers, cockscombs, spurs, etc. under the skin of rats. As you can see, the scientist paid tribute to xenotransilantacip. The Burgundian wits were quite sophisticated about the legend of the rat with a trunk. The source of this legend was Paul Ber, who transplanted the tail of one rat onto the nose of another.

Since Beru was not able to repeat Baronio's experiments on successful skin grafts, he was skeptical about all reports of successful skin allotransplantation in both animals and humans, transferring this skepticism to the success of allotransplantation in general. And yet, thinking about the possible outcomes of auto-, allo- and xeno-transplantations, Behr, in principle, did not exclude the possibility of a successful solution to this problem.

It must be said that skepticism about the successful outcome of allo- and xenotransplantation prevailed almost until the 20s of the 19th century, and there were quite good reasons for such an opinion. Despite all the tricks of experimental and clinical surgeons, it was usually not possible to engraft an allogenic graft. With the development of vascular surgery, in particular, after the appearance at the beginning of XX. v. works of Alexis Karrel, in which the method of direct suture of blood vessels was developed, during organ transplants, the connection of the blood vessels of the graft with the vessels of the recipient began to be used. The era of numerous observations of the behavior of allogeneic grafts began; The assortment of transplanted organs has increased dramatically, so to speak.

Already in 1912, Gutry, who was working with Carrel, wrote: “And although many experiments were described, no one succeeded in keeping an animal with a kidney or kidneys transplanted from another animal alive for any long period of time after his own kidneys were removed ... The prospect is by no means hopeless, and the principles of immunity, which have brought such brilliant results in many other areas, are worthy of study in this case. " To date, a large amount of data has been accumulated confirming that immunological incompatibility is the main reason for organ transplant failures. Therefore, the success of transplantation of vital organs is now associated not only with the improvement of surgical techniques (this issue can be considered resolved), but also with the solution of many immunobiological issues, in particular with the problem of tissue incompatibility.

*(Cit. according to the book: Transplantation of organs and tissues in humans / Ed. F. Rappoport, J. Dosse. M .: Medicine, 1973, p. thirteen.)

Over the past 20 years, interest in the problem of organ transplantation has increased significantly. Moreover, concrete ways are already outlined to guarantee the success of such operations. First of all, this is the selection (selection) of a donor and a recipient, the study of the tissue compatibility system in humans and animals and its assessment, the development of drug immunosuppressive therapy schemes, the use of specific sera and protein preparations (the so-called anti-lymphocyte globulin, etc.), the determination of early diagnostics of signs of transplanted organ rejection, etc. The complex application of all these measures has already led to certain results.

Modern transplantologists carry out transplantation not only of skin and bones, but also of various organs in humans. The successes achieved with kidney transplants have stimulated numerous attempts to replace other organs with transplants of the same name. Representatives of many specialties - experimental doctors, physiologists, biochemists, morphologists, immunologists, engineers, etc. such important tasks as engraftment of a graft taken from a genetically foreign donor, the ability to control the reaction of tissue incompatibility, long-term storage of isolated organs, and many others. dr.

According to world statistics, as of January 1, 1976, 23,915 kidney transplants have been performed on the globe, as a result, 10850 patients are alive, 52 of 288 patients with heart transplants live. In addition, 325 liver, lung, and endocrine gland transplants were performed. By this date, 29 people are alive.

However, the development of transplantology in its modern understanding was preceded by a long period of numerous experiments and searches. And among the pioneers of this science, one can safely name Paul Beer, who owes not only the merit of generalizing the observations already known and described in the literature by that time, but also the implementation of many experiments, for the first time drawing attention to facts that have not yet been satisfactory and final explanation. Even in the second half of the XX century. it was possible to only partially overcome the difficulties that Ber wrote about in his dissertation.

As you know, with a true transplant, the graft completely loses all ties with the donor's body, and it is connected with the recipient's body only through the humoral route: the transplantation operation ensures that only blood circulation in the graft is restored by connecting its vessels with the recipient's blood vessels. Thus, denervation or, rather, decentralization of the graft, becomes an important factor that necessarily takes place, although it is nonspecific only for transplantation. The consequences of this decentralization are especially noticeable in transplants of organs rich in striated muscles, such as the upper or lower extremities. Internal organs (kidney, heart, intestine, etc.) are not indifferent to decentralization, although autonomous reactions play a prominent role in their life.

In his dissertation, written during the discussion about the role of nerves for the graft (whether they have multiple functions, or their task is only to transmit impulses of a dual nature - sensory and motor), Behr paid a lot of attention to these factors. Referring to his own research, as well as to the work on nerve transplantation carried out by Philippe and Vulpian, he emphasized the importance of the trophic role of reinnervation. Already in those years, Behr, discussing the patterns and originality of the transplantation operation, postulated the twofold nature of this surgical intervention: in this case, animals experienced, on the one hand, a complete or partial (in the case of autoplasty) loss of initial connections with the donor's body, on the other, a different tendency , which Ber characterized as "the continuation of life, triumphing over the inevitability of death and existing most often in the new conditions of a new environment" *.

*(Bert P. De la greffe animalo, p. eighteen.)

A special place in Beer's research was occupied by experiments on parabiosis, which he also attributed to one of the transplant options.

The transplant model in this case was solved simply and gracefully. The objects of the experiment were white rats. On the skin of the abdomen in one - on the right, in the other - on the left, longitudinal incisions were made, skin flaps were removed, and the bleeding surfaces were connected with sutures and a colloidal bandage. After 5 days, the animals appeared to be fused with each other, resembling Siamese twins. Ber called this form of transplant "convergence transplant, or Siamese".

Such a transplant was a convenient model for demonstrating the possibilities of cross-circulation: drugs administered to one animal caused a corresponding reaction in another. Behr repeated his experiments many times and stated that it is possible to create cross blood circulation not only in animals of the same species, but also between animals of different species, for example, a rat-cat pair: belladonna, introduced into the cat's body with the help of an enema, caused pupillary dilation in the rat. Beru was unable to obtain similar data in a pair of rat and guinea pig. He did not find an actual explanation for this phenomenon and only suggested that the development of cross circulation in such a pair of animals could be hindered by differences in the size of erythrocytes. However, more interesting and perhaps ahead of its time is Beer's assertion that the "zoological distance" between species is to blame for the failures of transplants of this kind, as well as in cases of incompatibility revealed during blood transfusion. Isn't this thought a rudimentary form of the idea that in the development of the reaction of tissue incompatibility, genetic differences of an intra- and interspecies nature come to the fore?

Drawings from the work "Organ Transplant"

The ideas behind the cross-blood circulation model are still relevant today. Back in the middle of the 19th century. for physiological studies of organ function, the so-called organ perfusion was introduced and widely used. Isolated on the spot, that is, in the body of an animal, or organs completely removed from it, were washed with the blood of another animal or with various solutions. Having thus preserved the normal vital activity and function of organs, it was possible to study their reactions to various stimuli, pharmacological substances, etc. This technique is widely used in modern transplantology. It allows you to solve many issues and, above all, those that arise in the study of early specific and nonspecific reactions manifested in the graft and in the recipient's body. For example, the method of cross-circulation with a healthy donor is used to isolate a patient's heart during surgery. Of course, now, when performing this kind of procedure, the blood group of the donor and recipient, a number of hemodynamic factors are taken into account, and the main blood vessels are also used. But the basic idea of ​​the possibility of achieving a therapeutic effect with the help of cross circulation remains unchanged today.

Behr believed that over time, transplantation will take a large place in physiology and surgery. The scientist prophetically warned about the need to take into account in such operations a variety of factors that can affect a successful outcome: the health status of the donor and recipient, their age, the type of transplant, the state of its innervation, etc.

Critics praised Paul Beer's work "On Animal Transplant". At the same time, it was emphasized that transplantation can become the starting point of an important experimental method that allows not only to reveal the viability of tissues under special conditions, but also to study the effect of various substances on isolated tissues. These questions were further developed in Beer's doctoral dissertation "On the viability of animal tissues" (1865). The scientist summarized in it the results of his experiments to elucidate the influence of various physical and chemical factors on the ability of living tissues to carry out the basic phenomena of life. The work was dedicated to the memory of Pierre Gratiole and Beer's favorite teachers - Claude Bernard and Milane-Edwards, whose scientific concepts had a great influence on the formation of Beer's views as a natural scientist.

By the time this dissertation was written, natural science had already formed quite clear concepts and terms concerning the phenomena that determine the state of vital activity of an integral organism, the foundations of modern ideas about the physiology of animals and humans had been laid. By 1865, it was also known that tissues (or anatomical elements) in animals, like in plants, can exist in isolation for some time, that is, have "their own life, independent of the body to which they belong" * ...

*(Bert P. De la vitalite propre des tissus animaux. Paris, 1866, p. 2.)

The title page of Paul Beer's work "On the viability of animal tissues" - a thesis for the degree of Doctor of Natural Sciences

Behr emphasized that the "anatomical elements" of the body that make up the organism are located in a certain relationship and have various forms of special activity, which manifests itself only under certain conditions. He wrote about the need for in-depth knowledge of the essence of vital activity not only of the organism as a whole, but also of its individual parts. "The functions performed by living things, especially those that seem to have the highest degree of unity, are only the product of dynamic coherence, the synergy of multiple anatomical elements, harmoniously united." Behr considered Claude Bernard in France and Virchow in Germany to be his teachers in this matter.

*(Bert P. Do la vitalite propre des lissus animaux, p. 3.)

It should be noted that during the period when Behr was writing his dissertation, ideas about the chemistry of metabolic processes in various organs and their metabolic characteristics were still in their infancy. Biology of modern Beru did not have facts about the "nutritional characteristics" of living tissues. There were no methods for assessing tissue viability. Therefore, the time and nature of the onset of irreversible changes in organs exposed to modifying agents was extremely difficult to establish. The only acceptable then, from Beer's point of view, was the transplant procedure; it made it possible to identify phenomena requiring long-term observation. Therefore, Behr, in order to identify the patterns of the viability of various tissues, widely used the method of transplantation in his work, which he was excellent at.

It must be said that, despite the significant progress in the field of organ transplantation achieved by our contemporaries - scientists of the second half of the 20th century, many issues related to the concept of viability have still been resolved. Until now, much attention is paid to the concept of "viability" in scientific discussions, even special conferences are organized to discuss it: it is very important for scientists to have a unified point of view both on how to assess the suitability of an organ for transplantation and to characterize its condition after transplantation. However, it has not yet been possible to achieve unity on this issue.

In this regard, it is appropriate to recall that Behr summarized the results of his research on the viability of living tissues 12 years before the publication of the famous work of F. Engels "Anti-Duhring". In 1877, F. Engels put forward the proposition that ((life is a way of existence of protein bodies, and this way of existence consists in essence in the constant self-renewal of the chemical constituent parts of these bodies. " - time, although over the past 100 years since then, many provisions of natural science, especially in the field of molecular biology, have been revised. , as the ability to self-organization and self-healing.This ability is inherent in many biological systems at various levels of organization of living nature, since the features of self-organization and self-healing are inherent in biochemical systems, and cellular organelles, and cells, tissues, organs, physiological systems, the body as a whole, etc.

*(K. Marx, F. Engels, Soch. 2nd ed., V. 20, p. 82.)

Using the method of transplantation as the only available means of elucidating the nature of the viability of various animal tissues, Behr was actually the first who drew the attention of researchers to the fact that an organ or part of the body, for example, a paw or tail, in a warm-blooded animal, as well as none of the anatomical elements that make up this organ do not die immediately. Behr considered the manifestation of the ability to grow, the presence of sensitivity, and other properties that such an isolated organ can show several days or even weeks after it is transplanted under the skin or intra-abdominal to another animal as direct evidence of the viability of such an organ. True, Beer's views on this issue were not particularly clear: in his opinion, the disappearance of individual properties is not yet a signal that the organ as a whole is not viable. But now, more than 100 years later, one should hardly be particularly strict with these views of Bera, since, as mentioned above, there is no single point of view on this issue to this day.

The level of development of the science of that time did not allow Ber to talk about the energy supply of tissues, the violation of which, under conditions of altered blood circulation during transplantation, gradually leads first to insignificant, and then to deeper disorders of vital processes. But Ber assigned the leading place to the restoration of "nutritional conditions".

Vulpian (1864) bandaged the green frog's aorta for over three hours. Several hours after the restoration of general blood flow, he received reversibility of functional disorders in the limbs. Behr believed that the same effect could be observed in similar experiments on newborn rabbits, but provided that artificial respiration was started at the moment of removing the clamp from the aorta. The discussion about the timing of the onset of irreversible changes in various tissues does not stop today, and it is not surprising - after all, establishing the fact of the viability of various organs is of great importance not only during their transplantation, but also in the treatment of injuries and surgical interventions.

Our contemporary, the famous French surgeon Lerisch wrote: “The problem of slow tissue death caused by ischemia is still not completely resolved if we consider it from the point of view of the vital activity of the tissues themselves. And although this issue is of great practical importance, surgeons were interested in it especially practically. Theoretically, they solved the issue too radically and at the same time elementary ... ". Indeed, for some reason, surgeons were somehow lazy to analyze and differentiate between dead and dying tissue. Few of them were sufficiently interested in how and why tissues die. It seems to me personally that the tissues, before dying, agonize for a long time "*.

*(Lerish R. Fundamentals of physiological surgery. L .: Medicine, 1961, p. 98.)

Currently, in the arsenal of the surgeon there are many techniques that make it possible to prolong the viability of tissues, to lengthen the period during which it is still possible to count on the restoration of the function of an organ isolated from the body. These include various methods of conservation, including cooling, as well as the use of heart-lung machines, pressure chambers, various preservative media and solutions, etc.

But in Beer's time, only the first steps were taken to establish patterns that would preserve tissue vitality. Based on the results of his own experiments, Behr made the following conclusion: the characteristic properties of a particular tissue do disappear rather quickly, but it is quite obvious that these losses are due to new conditions in which the removed element falls; if the right conditions are created for the tissues and organs, they can exist in the same way as in the body.

Behr identified three categories of physiological properties. One of them includes the properties that provide movement - sensitivity, reflexivity, contractility, motor function. Changing their anatomical connections gives an immediate response. Fertilization and the development of a new being fall into another category. Changes in these properties occur more slowly, but they are so obvious and occur on such a scale that they can be seen with the naked eye. The properties of the third category are of such an intimate nature that they have little effect on the external state of the organ, therefore it is extremely difficult to ascertain them. It is extremely difficult to grasp their very slow changes. In Beer's opinion, the properties of this last category are associated with elementary nutrition of cells, that is, in the language of modern functional biochemistry, their changes should be attributed to metabolic changes.

In this respect, Ber turned out to be, perhaps, a good soothsayer - after all, today transplantologists experience great difficulties in determining the state of metabolic processes in an isolated organ before transplantation. Attempts to predict the degree of reversibility of pathochemical changes during the so-called period of "acute ischemia" (that is, while the graft was completely isolated from the circulatory system and, therefore, did not receive either oxygen or nutrients, was unable to remove metabolic products substances) do not always give reliable results.

In addition, Ber, as it were, foresaw the "exchange for function" and "exchange for oneself" already described by our contemporaries, when in one case an isolated organ retains the intensity of metabolic processes to the extent that it allows the resumption of functional activity immediately after the restoration of blood flow in it. while in another case, his vital activity is significantly reduced. Therefore, after the resumption of blood circulation in such an organ, it takes some, sometimes rather long, time to restore the controlled function. And until the function is restored, the organ is not able to participate in the general ensemble of the body. Such an organ cannot be called "dead", although it is very difficult to judge its viability.

Analyzing the prospects for the existence of a transplanted organ under new conditions, Bohr introduces the concepts of "external conditions", identifying them with "environmental conditions", and "internal conditions", which are synonymous with "elementary properties" subject to changes from external conditions. And although Ber does not always give a clear meaning to the concept of "elementary properties", the main idea of ​​their variability under the influence of the external environment is carried out in his work quite consistently.

For example, cold first slows down and then leads to the disappearance of the movements of the ciliated cilia, while heat promotes the resumption of motor activity. Therefore, Behr believes, when characterizing this or that property of living tissue, it is imperative to name the conditions observed when setting up an experiment. You can't just talk about the contractility of myofibrils. It is imperative to indicate, for example, temperature conditions, since at temperatures above 45 ° C in mammals, contractility disappears. In essence, Behr approached the study of the problem of organ preservation, laid the foundations for ideas that have not lost their relevance today.

In his dissertation, Ber set out not only to collect new material to demonstrate the "vital independence" of tissues, but also to study the effect of different media on the preservation of the properties of living tissue, or, in other words, to find out the resistance of their properties to the influence of different media. He conducted his experiments on white rats, which, due to a number of species properties (small size, skin laxity, low suppuration ability), were a convenient biological material for transplanting (more correctly, replanting) fragments of various organs into the subcutaneous tissue. Less often, the same manipulation was performed intraperitoneally. The main type of transplant was a rat's tail transplanted subcutaneously onto the back (along the midline) of another rat. The fact of growth under new conditions served as a criterion for success - Ber considered the registered growth to be the main sign of the preservation of the viability of the transplanted organ.

Behr paid much attention to the temperature factor. By this time he was well aware that at a temperature of 51 - 52 ° C birds die; But do bones, tendons, muscle elements die in this case? It turned out that the temperature conditions for the death of various tissues are different. Particularly favorable results were obtained when the future grafts were cooled: storage for 22 - 48 hours at a temperature of 11 - 12 ° С not only in air, but also in water, did not reduce the ability of the rat tail to grow after transplantation. Ber also transplanted organs from the corpse, and took them even 20-30 hours after the death of the animal. And the experimenter always observed the same growth effect, provided that there was no temperature increase in the animal's corpse until the organ transplantation.

Behr did not define a temperature reduction limit consistent with tissue viability. However, his experiments are extremely interesting, because, for all their primitiveness, they opened up the prospects for the so-called cold preservation, the latter has already been greatly developed in our time in a variety of ways as applied to any transplanted organ, not only in experiment, but, which is much more important, in the clinic.

Seeking a broader approach to the development of the questions posed, Behr made many experiments to study the effect of various gases on the behavior of the graft. The scientist showed that oxygen and hydrogen taken as storage media did not retard the growth of the transplanted organ even if it was stored for more than two days. The mixture of oxygen (up to 80%) with nitrogen also had no toxic effect on the graft. Somewhat worse, the graft was preserved in an atmosphere of carbon dioxide; however, lowering the temperature of the transplanted organ to 11 - 15 ° C made it possible to extend its shelf life up to 47 hours.

Other gaseous substances, vapors of phenol and gasoline, contributed to the transformation of the graft as fatty degeneration, and ether, ammonia, carbon monoxide caused its complete destruction. Ber received a negative effect when using carbon dioxide, hydrogen sulphide, sulfuric acid vapors. According to the scientist, this result was the result of the acidic reaction of these substances. The graft was poorly preserved in solutions of neutral salts: even their relatively low concentrations caused damage to its tissues.

The great advantage of Beer's research on the viability of grafts in comparison with other works in this area is the length of the observations. It was this circumstance that allowed the scientist to draw the following important conclusion: the methodology used - replanting tissue or a piece of an organ, in which, in his opinion, the method of "tissue nutrition" in a living organism is preserved - is convenient for assessing the viability of a graft previously subjected to various influences. Interestingly, Behr even noticed vascular ingrowth and restoration of neural connections between the graft and the recipient. He documented his dissertation with illustrations confirming these facts.

Beer's first steps in the scientific field vividly testify to his uncommonness as a researcher, his ability to analyze and generalize scientific facts, to draw bold conclusions, often ahead of the era in which he lived and worked.

Of course, to our contemporaries, many of his experiments seem primitive, perhaps even too exotic. But after all, in Beer's time, the vascular suture was not yet developed, which enabled surgeons to fulfill the basic requirement for organ or tissue transplantation, which Behr postulated - give the transplant "nutritional conditions" close to natural, and it will retain its vital properties.

Unfortunately, Behr did not continue his research in the field of organ transplantation and elucidation of their viability. The development of his scientific thought went in a different direction. However, the scientist's main ideas about the viability of tissues, about the influence of various factors on them, including a modified gas environment, apparently, were the basis on which his fundamental research was subsequently created and developed in the field of studying the role of the barometric factor in the life of animals and plants. anesthesiology, etc.

Botanical observations and experiments

The work of Bera the biologist is permeated by the idea of ​​the unity of vital processes in animal and plant organisms. The very desire of the scientist to substantiate the concept of "animal grafting", along with the generally known plant grafts for gardeners and plant breeders, indicates the desire to deepen the parallelism between the two kingdoms of nature. Just like Charles Darwin and many other major biologists of that time, Behr understood that neither evolutionary nor any other general biological theory can acquire a complete form without being tested also on botanical material. Just like Charles Darwin, Behr paid special attention to the long-time mysterious phenomena that bring animals and plants closer together in their ability to move - a feature that at first glance most clearly contrasts them with each other.

The beginning of research on various problems associated with certain types of movements in plants dates back to the 18th century. It was then that C. Linnaeus first announced the "dream of plants", referring to cases of unequal arrangement of plant organs in the daytime and at night, ie, nyctinastic movements. Linnaeus spoke of the "dream of plants" in a literal and not a metaphorical sense, identifying it with the sleep of animals. In the same period, C. Bonnet conducted experiments to elucidate the causes of geo- and phototropic movements, as well as the rhythms of movement. However, his data brought little new, and K. Linnaeus's observations on the movement of leaves for a long time remained the main source of knowledge in this area, and the concept of plant sleep (in a figurative sense) has remained in the literature to this day.

Mention should also be made of the work of G.L. Duhamel (1758), who studied rhythmic (endogenous) movements as well as those caused by external stimuli. He believed that the rhythmic movements of the leaves also occur in constant darkness, that is, in the absence of alternation of periods of light and darkness.

At the beginning of the XIX century. interesting research on the mechanism of leaf movements was carried out in France by I. Dutrochet. His experiments had a great influence on the subsequent development of the problem. The experiments of the English botanist K. Knight, who established in 1806, that the reason for the orientation in space of roots and stems is the force of attraction, also belong to the same period. Under its influence, the stems are directed upward, and the roots - downward, i.e.. the former have a negative, and the latter, a positive geotropic reaction. Knight also pointed out the presence of positive and negative phototropic reactions in plants. However, in explaining their reasons, he, like Dutrochet, limited himself to a purely mechanical approach. This gave their works, as well as the works on phytodynamics of many authors of the first half of the 19th century, a somewhat one-sided, mechanical character.

Among botanists of the first half of the 19th century. a sharp discussion was caused by the question of the causes of movement in plants, especially in mimosa, mainly the dispute unfolded between the supporters of the Dtohamel hypothesis. (earlier it was expressed by J. Turpefort), who believed that plants move according to the principle of contracting muscles, the role of which can be played by hygroscopic vascular formations, and supporters of the Dutrochet theory, who are inclined to see the reason for the movement of plants (including rhythmic and artificially induced ones) in a change in turgor cells, which is determined by the ratio of exosmosis and endosmosis. In the middle of the XIX century. Controversy erupted in connection with the work of Brueckx, who established a difference in the nature of the movements of mimosa leaves, caused by irritation and beginning with the onset of evening, and with the works of J. Saks (1832 - 1897), who approached the solution of these issues from an adaptive-functional point of view.

In general, we can say that by the middle of the XIX century. the main forms of movement of higher plants have been described, at least from the outside. Observations of the periodic movements of plant organs, for example, changes in their position depending on the change of day and night, or movements caused by the action of direct stimulation, have been carried out for a long time, but remained, as it were, in the shadows, not in the center of the experimenters' attention. Botanists have long been fascinated by the problems of plant anatomy, morphology and taxonomy. Issues of phytodynamics, i.e., the description of the mechanics of plant movement, most botanists until the middle of the 19th century. did not attach paramount importance *.

*(See: Sachs J. Geschichte der Botanik vom 16. Jahrhimdert bis 1860. Munchcn, 1875, S. 578-608.)

The situation changed at the beginning of the second half of the 19th century. as a result of improving the methods of plant physiology and in connection with the formulation of new questions related to ecology and the evolutionary significance of plant movements. In 1865 - 1875 Ch. Darwin and his son F. Darwin were engaged in research in the field of phytodynamics. At the same time, Ber worked on this topic. Beer's and Darwin's studies were carried out independently of each other, and Beer's main publications on plant movements appeared even somewhat earlier than Darwin's works on mimosa. True, Charles Darwin's works in this area are broader in their scope than Beer's works, and cover different types of movement: photo- and geotropic, nyctinastic, etc. plants depending on their systematic position.

It is interesting that in connection with attempts to reveal the effect of anesthetics (sulfuric ether) on natational movements in peas and passionflower, Charles Darwin relies on Beer's works and cites them. The doses of anesthetics used by Charles Darwip were insufficient and did not give a noticeable result. This was also noted by Charles Darwin, comparing the results of his experiments with Beer's observations on mimosa, which turned out to be a more convenient object *.

*(See: C. Darwin. Climbing plants. - Op. Moscow: Publishing house of the USSR Academy of Sciences, 1941, vol. 8, p. 138.)

In the second half of the XIX century. there have been many other studies of the problem of the movements of the plant organism. They were reviewed in due time by N.G.Kholodny *. In this regard, it is necessary to note the valuable contribution made to the solution of this problem by Russian biologists **.

*(See: Cold N. G. Charles Darwin and the doctrine of the movements of the plant organism. - Darwin C. Soch., Vol. 8, p. 5 - 34.)

**(See: Rachinsky SA On the movements of higher plants. M., 1858, p. 63; Batali AF Mechanics of movement of insectivorous plants. SPb., 1876; Rotert V.L.On movement in higher plants. Kazan, 1890; Artsikhovsky VM Irritability and sense organs in plants. SPb .; M., 1912.)

Behr limited the area of ​​his experiments to nyctinastic and seismonastic movements of plant organs. By niktinastic movements, or niktinasti, usually understand the movement of leaves or petals associated with the change of day and night; under seismonastic, or seismonastia, movements, which are the reactions of plant organs to a shock or touch. Both of these categories of movements are nasty - movements in response to the actions of stimuli that do not have a definite direction, in contrast to tropisms - movements or one-way growth in the direction given by an external stimulus. Ber chose mimosa as a test object for a reason. The leaves of this plant are capable of two types of movements: nyctinastic and seismic. Behr, using the example of mimosa, tried to solve a number of important general biological problems, for example, to clarify the anatomy and morphology of the physiological mechanisms of plant movement, to study their seismic and nyctinastic reactions. The anatomy and morphology of mimosa by that time were described in sufficient detail, and Ber, according to him, was able to make only some clarifications on this issue. The main results of his observations on mimosa relate to the physiological side of plant movements.

As you know, at the bases of the first-order leaf petiole and at the bases of numerous second-order leaves of mimosa there are articulations, the so-called pads. In the zone of these pads, changes occur, leading to seismonastic or noctinastic movements of the leaf. True, as Behr noted, already during his experiments, data appeared in the press that mimosa leaves have two types of "nastia" - seismic and nasty, but the author did not know about these works when he performed his experiments *. It was believed that both of these types of leaf movement are identical in nature: if nyctinastic, slow movements were taken for the natural sleep of plants, then seismic ones - for sleep caused artificially or by an external stimulus.

*(See: Bert P. Recherches sur Ics mouvements de la Sensitive (Mimosa pudica Linn.) - Mem. Soc. sci. phys. et natur., 1866, p. 11 - 46.)

Behr conducted a series of experiments to identify the features of these types of movements. In the course of the experiments, it turned out that in the daytime, the double-pinnate leaves of mimosa are directed towards the stem at a greater or lesser angle upward. The individual feathers of the leaf lie in the same direction, and as a whole, the leaf resembles a fan. At night, the main petioles bend downward so that the leaves "take on a drooping appearance", and individual opposite leaf feathers are pressed against each other in pairs. These slow movements are determined by bending of the pads of the first-order petiole of the main leaf and of the second-order petioles, that is, of the "feathers". Behr described his observations as follows: "During the day, the leaves of mimosa are widely spaced, and the petioles of its leaves are half-raised. After strong irritation, the leaves fold, and the petioles fall ... If the leaves of mimosa are too sharply irritated, their petioles become lethargic, and, conversely, firm and elastic they become when they are lowered. What was previously described as a nocturnal state in mimosa is actually just the end of the daytime period during which the petioles bend more and more. On the contrary, by 9-10 pm they quickly rise and reach maximum straightening in the period from midnight to two o'clock in the morning, after which they begin to descend again.I was able to trace the change of these states during numerous observations, one of which lasted 17 nights and 18 days. , indeed, brightly illuminating the mimosa at night, I observed that the leaves retain the state of maximum rise; and vice versa, with e When kept in the dark, the daily fluctuations decrease, the leaves stop in a bent position, and after a few days the plant kept in the dark may even die. "

*(Bert P. Recherches sur les mouvements de la Sensitive, p. 239 - 241.)

Mimosa leaves are also notable for the fact that, under the influence of chemical or other type of irritation, they change their spatial arrangement, produce seismic movements. The leaf petiole is lowered, and the petioles of the second order produce a movement in which the feather leaves are folded in pairs. Consequently, the mimosa leaf has a peculiar device responsible for its movement. Behr tried to reveal the physiological reasons due to which the motor function is carried out in mimosa. This line of research turned out to be very fruitful.

The first thing Behr drew attention to was the difference in the causes and mechanisms of the nyctinastic and seismonic movements. Analyzing the dynamics of these processes in the course of special experiments with the use of inhibitors, Behr noticed that nyctinastic movements are cyclical in nature. During the day, mimosa leaves describe a certain trajectory that characterizes niktinastic movement. In the evening, the leaf falls; then, a little earlier than midnight, it begins to rise; during the day, its petiole again descends to a certain angle, which is greater than in the morning hours, but smaller than in the evening. Seismonastic movements are characterized by a similar regime: during these movements, the leaves undergo spatial movements, similar to those that occur during niktinastia. True, with seismic events, the process occurs as if in an accelerated form.

Wanting to be convinced of the reliability of the observed differences in the dynamics of movements, Behr used various substances. He believed that some of them will give some result and show selective action in relation to these movements. Sulfur ether proved to be suitable for this purpose beyond his expectations. Plants, being under the hood in the vapors of sulfuric ether, lost their ability to move seismically; the nyctinistic movements remained at the same time. Plants passed into a state where the leaves, making movements according to a diurnal rhythm, did not respond to mechanical stimulation with seis-monastic movements. It was noted that sulfuric ether had a reversible effect in relation to seismonastic movements. Plants removed from the medium of ether vapors again restored their ability to seismonastic movements: under the influence of mechanical stimulation, their leaves sank down, and opposite leaf feathers simultaneously approached, resembling a half-open fan *.

*(Bert. P. Recherches sur les mouvements de la Sensitive, p. 11 - 46.)

Let us note that several decades later these data were fully confirmed by the Indian scientist, the classic of plant physiology J. Bose, in his work on the "nervous mechanism" in plants. Among the various poisons he tested, sulfuric ether showed special properties: moderate doses of sulfuric ether vapor not only did not inhibit plant growth, but even accelerated it. Bose obtained clear results showing that at doses of ether that do not kill plants, the latter loses its excitability. But when the vapors of this drug evaporated, the plant gradually returned to its usual sensitivity *.

*(See: Bose J. Ch. Selected Works on Plant Irritability. Moscow: Nauka, 1964, vol. 1, p. 212 - 218.)

The most convenient model for studying the mechanism of leaf movement was the seismic response.

Behr confirmed the presence of the following links of seismonastic movements in mimosa: irritation, transmission of irritation, response phase of the reaction. The organs that are most sensitive to irritation are the pads of the main leaf petiole and leaf petioles. The ability of irritability, according to Yu. Saks, depends on temperature. Ber once again testified that at low temperatures, as well as at high temperatures, which also have a negative effect on the plant, the ability to irritate is lost; transmission of excitation can occur in all directions, but its speed is greater in the basipetal than in the acropetal direction. This applied to both the leaves and the stem.

Before Beer, the rate of transmission of excitation in mimosa was measured by I. Dutrochet. He found that irritation is transmitted at a rate of 8-15 mm / s in the leaves and 2-3 mm / s in the stem. According to Ber, the rate of transmission of stimulation turned out to be lower - 2 mm / s. It has now been established that the data on the magnitude of the rate of transmission of stimulation, obtained by Ber, are underestimated, and usually excitation is transmitted at a speed of 4-30 mm / s *.

*(Bose J. Ch. Selected Works ..., vol. 1, p. 237 - 251.)

However, Behr did not mainly strive to determine the absolute rate of transmission of stimulation, which varies depending on the properties of an individual plant, environmental factors, etc. His main goal was to show that plants and animals have similar systems of perception and realization of the effects of stimulation. This is the undoubted general biological significance of these works of the scientist.

Speaking of irritation, we had in mind mainly mechanical stimuli. However, the general conclusions drawn by Berm can be attributed to other types of stimuli: when using them, the same final result was often obtained, although the scientist used very different stimuli: mechanical (contact, prick, cut), physical (heat, electricity), and chemical (acids and other compounds). Having described the reactions or dynamic processes that occurred in response to stimulation, Behr proceeded to study the deeper patterns of the motor process in plants, striving to get closer to an adequate understanding of its essence, which manifests itself in seismic-nictinastic movements.

The first thing that attracted Beer's attention was the state of osmotic forces in the zones of the petioles, which are responsible for the motor function of the leaf. Almost 20 years before his research, it was found that the movement of mimosa leaves is accompanied by a change in turgor ratios in the petiole pads during nyctinastic and seis-monastic reactions: at the first, turgor pressure increases, at the latter, it decreases. It was also known that, regardless of the removal of the upper half of the pad, the diurnal rhythms of movement and the induced movement of the leaves were maintained *. From this it followed that the movement was determined by a change in turgor in the lower half of the pillows.

*(See: Sachs J. Geschichte der Botanik vom 16. Jahrhundert bis 1860.)

To clarify the above factors, Behr performed a series of experiments using water and glycerin as agents capable of changing the turgor state of cells. In one of the experiments, he removed the upper half of the petiole cushion, which makes an angle of 100 ° with the stem, and applied a drop of glycerin to the cut surface. As a result, after 10 min, the bending angle decreased to 50 °. When a drop of water was applied to the cut, the turgor in the cells increased and the angle between the leaf and the stem increased from 85 ° to 120 °. After repeated processing of the petiole with glycerin, the angle decreased to 60 °, and in the evening, after 8 hours from the beginning of the experiment, it assumed its original position. An increase in turgor pressure did not interfere with the response to stimulation - the leaves remained seismically sensitive *.

*(See: Bert P. Recherches sur les mouvements de la sensitive ..., p. 38 - 42.)

The experiments of Beer and other researchers of the nature of movement in plants revealed the reason for this phenomenon: in the cells responsible for movement, turgor changes, i.e. the tension of the cells becomes different. This is the most important difference between the movements of plants and animals, since in the latter, the motor function is performed by muscles capable of contracting.

The turgor forces do a certain job. Behr tried to determine them experimentally, using the leaf load, which causes the petiole to bend and is equal in magnitude to the load during seismic leaf movements. It turned out that the leaf, making movements, performs significant work, which is impossible without a certain source of energy. The researcher was faced with the question of the direct use of the concept of "energy conversion" to study the motor process in plants.

Apparently, Behr had a fairly clear idea on this issue. His works date back to the period when the law of conservation and transformation of energy was finally established in biological science thanks to the research of R. Mayer and especially H. Helmholtz. It was obvious to Beer that in leaf work, as in muscle work, the use of chemical energy leads to the release of heat. But what about the quantitative measurement of at least the temperature change during leaf movements? Naturally, ordinary thermometers were unsuitable for measuring small temperature deviations. Then Behr, with the assistance of the physicist P. Rumkorf, developed a special thermoelectric instrument, and with its help he measured the fluctuations in leaf temperature by means of thermocouples, which in the form of needles were inserted into the petiole tissue. This most sensitive instrument is used in physiology and at present for the purpose of measuring minor deviations in the temperature parameters of a plant.

One of the first results of Beer's measurements was the establishment of the fact of the unequal temperature of various tissues of the stem and leaf of a plant. The temperature in the petiole pads was lower than in the adjacent area of ​​the stem or in individual internodes. In addition, the plant's own temperature turned out to be unstable during the day, but these tiny fluctuations were difficult to measure. Behr could not measure the temperature of the leaf feathers, but correctly assumed that, due to transpiration, it would be lower than the temperature of the stem.

Beer's very original experiments were among the first of this kind. Carrying out them, the scientist did not just compare the temperature in the individual organs of the plant. He was interested in the nature of the relationship between leaf movement and the possible release of energy in the form of an increased temperature of the tissue responsible for motor function. Beru was able to establish two possible ways of converting energy. During the noctinastic movements of the leaf, the temperature of the petiole pads was lower than in the stem and decreased as the leaf moved. When the leaves descended at the petiole joints, the turgor fell, the cell volume decreased, and the cell sap was squeezed out into the intercellular spaces. Evaporation of water could also be a possible reason for the decrease in the temperature of the petiole joints. Beru was able to show that the process uses energy. Among chemical reactions, in this case, not oxidation reactions should prevail, but the reactions of reduction, hydration and dehydration, which are characterized by the conversion of chemical energy into heat.

Behr considered the nature of the seismic movements of the leaf in connection with the transformations that are determined by chemical processes that occur with the release of heat, that is, reactions with a predominance of oxidation. When studying noctinastic movements, the methods of measuring temperature shifts chosen by Berm could not provide definite data on the biochemical transformations accompanying the use of energy by a plant. To clarify this question is still to be done by modern researchers. However, Ber was far ahead of his time in his striving to link seismonastic movements with the transformation of energy.

Nowadays, Beer's experiments attract a well-deserved interest, especially in terms of research on biological systems for the conversion of energy. It is now known that both animals and plants, including bacteria, use the cycles of conversion of adenosine diphosphoric and adenosinteriphosphoric acids to carry out energy-intensive processes. In particular, the experiments of M.P. Lyubimova (1899 - 1975) * are directly adjacent to Beer's experiments. Together with her colleagues, she studied the changes in the ATP content in the leaf pads of mimosa, where the motor cells that determine the motor function of the leaf are located. It turned out that the pads have an increased concentration of ATP (19-24 μg ATP per 1 g fr wt), and more ATP is contained in those of them that are actively involved in leaf movement. The movement of the leaf, caused by mechanical irritation, leads to a sharp decrease (up to 30 - 50%) in the concentration of ATP in the pads. Later, when the irritation of the leaf ceases, the ATP content in them is restored again, approaching the initial level. These and other data obtained in experiments with plant objects indicate a certain analogy of their movements with the motor function of the muscles of animals, in which ATP is also the energy supplier.

*(See: Lyubimova M. Ya., Demyanovskaya N.S., Fedorovich I.B., Itomlenskite I.B. 4, 29, p. 774 - 779.)

What substances change the osmotic parameters of cells? What chemical compounds are used as a source of energy in the exercise of motor function? Are niktinastic movements determined only by the change in the daily photoperiod, and do individual rays of light (different parts of the spectrum) have different effect on leaf movement? These questions were faced by Ber when he continued his studies of plant movement. The scientist tried to give the most comprehensive answers to them by setting up a series of special experiments.

The experiments were preceded by the development of a hypothesis that the substances involved in the regulation of osmotic pressure in cells are created in the light. The same substances are also used as a source of energy for doing work in movements. Ber considered starch to be such a substance, which, upon hydrolysis, gives glucose, and the latter constitutes an osmotically active compound. Consequently, according to Beer, a change in the ratio of starch and glucose in the cell changes the strength of osmosis and cell turgor. This fundamentally correct position has not lost its significance today: osmotic pressure is similar to gas pressure, being proportional to the number of particles of a dissolved substance in a certain volume of solvent. It does not depend on the nature and weight or the size of these particles. If we consider the cell as a certain volume in which the active substance, which determines the osmotic pressure, dissolves, it becomes obvious that the starch-glucose system adopted by Beer fully meets these requirements.

Light in Beer's experiments was considered both as a source of energy for the synthesis of carbohydrates, and as a possible immediate stimulus. In this regard, a series of his experiments with the use of light filters should be noted.

What part of the spectrum is necessary to maintain normal physiological processes of the ability to move in plants: the region of visible or infrared radiation, which gives the greatest amount of heat, or that part of the spectrum to which the retina is most sensitive, or, finally, short-wave rays, which are chemically most active? In search of an answer to this question, Behr went beyond the problem of plant movement and touched upon such general physiological aspects as the influence of rays of different wavelengths on the absorption of carbon by plants, the formation and destruction of chlorophyll, etc.

To study the activity of individual parts of the light spectrum, two methods could be used: the decomposition of the light beam into parts of the spectrum using a glass prism, or the use of screens made of colored glass (or from colored solutions), which would transmit a part of the spectrum with a known wavelength. Behr preferred the second method, although he was aware that it would not allow obtaining a monochromatic beam of light. In this respect, the first, spectroscopic method is suitable, but its application was associated with a number of technical difficulties, which Ber could not overcome. For the first time, only K. A. Timiryazev * succeeded in using the spectral method flawlessly in the study of physiological processes in plants. To a large extent, as a result of this use, K.A. Timiryazev came to his classic discoveries in the field of photosynthesis. It is interesting that Ber was one of the first to appreciate ** the high value of Timiryazev's experiments, which showed the highest intensity of photosynthesis in red rays.

*(Senchenkova E. M. K. A. Timiryazev and the doctrine of photosynthesis. M .: Publishing house of the Academy of Sciences of the USSR, 1961, p. 75 - 98.)

**(See: Bert P. La lumiore et los etres vivantes. - In: Bert P. Lecons, discours et conferences. Paris, 1881, p. 248.)

But let us return to Beer's experiments. In them, he used red, yellow, green, purple and blue filters. They did not transmit monochromatic light, although Behr was aware of the need to use it to summarize the final results. Red filters were distinguished by the highest homogeneity of light, followed by yellow, green, etc. Red rays were most favorable for the growth, life and movement of mimosa. Plants exposed to red light for a long time retained both types of movements described above.

Behr also discovered the formative effect of light on plants: they grew in red light, but their stems were excessively stretched in length. Mimosa plants growing in green light did not differ from those. who were in the dark: they lost the ability to move and after a while died.

Here is how Behr described one of his experiments to elucidate the reaction of plants to illumination with rays of a limited portion of the spectrum: “I put mimosa in an apparatus arranged like a lantern equipped with colored glasses. , the plant, in three to four days, almost as quickly as in complete darkness, loses its sensitivity and life.

I repeated the experiment on plants belonging to different families and characterized by very different life rhythms: the result was the same, death within a few weeks affected all the plants covered with green glass. Notice that my green glasses let through all the colors of the spectrum, but of course with a predominance of green. Note also that we are talking about true green light, and not about the apparent light that our vision perceives when the object is illuminated by both blue and yellow rays. This green color does not kill plants.

Having stated this curious fact, I immediately found a very simple (in my opinion) explanation for him. If the leaves are green in reflected or transmitted rays, this means that from all parts of the spectrum they reflect or transmit as useless green rays. If, I said to myself, they were given nothing but these unused rays, then it’s not surprising that the plants perish: for them such illumination is equivalent to darkness. I became even more convinced of this when, in a further experiment, Mr. Kites proved that behind green glass, leaves do not decompose carbon dioxide. In reality, however, the situation is even more complicated. Quite recently, Mr. Timiryazev carried out new, very precise studies, from which he concluded that the maximum of the reducing effect of light on carbonic acid is located in the red part of the spectrum, containing the rays most intensely absorbed by chlorophyll. "*

*(Bert P. Recherches sur les mouvements de la sensitive ..., p. 247 - 248.)

Here Ber also emphasized the non-monochromatic nature of the light source and noted in this connection the importance of the high-precision experiments of K. L. Timiryazev (apparently, this refers to his dissertation "On the assimilation of light by a plant", 1875, as well as subsequent works).

In his lecture "The current state of our information on the function of chlorophyll," read at the International Botanical Congress in St. Petersburg in May 1884, Timiryazev noted the priority of the method used by Paul Ber in studies of the response of plants to different parts of the spectrum, over the analogous method of I. Reinke * ... In Beer's experiments, according to Timiryazev's formulation, for the first time the error arising from uneven dispersion was eliminated experimentally, although Beer's method, who mainly used not a prism, but colored filters, “is inconvenient in the sense that with him experiments are performed not simultaneously, but sequentially and therefore they demand that the tension of the light (of the sun) be constant throughout the entire experience "**. Timiryazev considered his prismatic method to be a further improvement of the "ingenious method of Paul Beer, proposed in 1878, which consisted in collecting rays of light previously spread out by a prism" ***.

*(See: K.L. Timiryazev, Op. M .: Selkhozgiz, 1937, vol. 1, p. 372.380.)

**(Ibid., Vol. 2, p. 251.)

***(Ibid, p. 261.)

Mimosa developed slightly better than under green illumination under conditions of the short-wavelength region of the spectrum: the plants retained their green color, but almost did not grow and were close to death. Explaining the reason for the unequal growth and vital activity of plants depending on the part of the light spectrum, Behr suggested that the physiological activity of light depends on the ability of a plant to absorb light of a given wavelength. For its life, mimosa uses all the rays that make up the white color, with the exception of green. The latter for her are equivalent to darkness, because chlorophyll does not adsorb them.

Behr considered the influence of light of different spectral composition on the life of mimosa in a generalized form, believing that the features he discovered apply to other higher plants. At the same time, he believed that the growth, for example, of various tiers of a forest as a community of plants is largely determined by the quality of light that the plants in the lower tiers receive. Later, ecologists focused their attention on the quantitative side of the phenomenon: in fact, the upper tiers of the community partially obscure the lower ones and, depriving them of a certain amount of light, enable only shade-tolerant plants to grow. With especially dense upper tiers, the lower ones can be very poor: for example, in a beech forest, the grass cover is very scarce. But the qualitative aspect of this phenomenon, its connection with the change in the spectral composition of light when passing through the upper tiers of the forest has not yet been fully elucidated.

Ber also showed the unequal composition of the luminous flux of the rays in relation to the movements of the mimosa leaf. Experiments have confirmed his assumption that the composition of the light beam affects the spatial orientation of the leaves. According to Beer's data, violet color stimulates the leaf's ability to close or open the most, followed by blue, yellow, red, green. The latter in its effect is almost equivalent to black, while daylight - white light is somewhat inferior to violet. Niktinastic movements are also modified when the composition of the light changes. In blue and violet rays, these movements are more intense than in red or yellow ones. Thus, it is easy to see that in the direction of the short-wavelength region of the spectrum, the activity of the rays in relation to the motor reaction of plants increases.

The increased sensitivity of plants in the blue-violet region of the spectrum is currently explainable: plants have an acceptor system that absorbs light in the range of 400 - 555 microns. This applies not only to the case described by Bohr, but also to other types of plant movements caused by light, for example, their phototropic movement *.

*(See: P. Boysen-Jensen, Plant Growth Hormones. M .; L .: Biomedgiz, 1938.)

Behr spoke about the importance of light in the life of plant organisms in a lecture read on March 19, 1878 at the Sorbonne *. The scientist tried to figure out how plants, through the use of solar energy, assimilate carbon dioxide and convert it into plastic compounds, which then in the process of respiration are again destroyed to the original simple molecules with the release of energy. In this regard, Behr put forward the task of more efficient use of the sun's rays in crop production, believing that through the use of rational fertilization methods, it is possible to help plants more intensively absorb solar energy. He questioned the need for plants to change periods of night and day. In his opinion, by increasing the daily lighting period, you can get a harvest in a shorter period. Behr believed that a plant needs a certain number of light hours to go through the growing season. In general, he was right: long-day plants, which include most of the cultivated species today, can go through a full development cycle under continuous lighting. Of course, for the practical application of this ability of plants, it is necessary to fulfill many complex conditions associated with both equipment and energy consumption, and with the adaptation of crops to the restructuring of ecological cycles.

*(See: Bert P. La lumiere et les etres vivantcs, p. 233 - 272.)

In the same report, Behr touched upon another important aspect of the effect of light on plants - its role as a source of energy not only for the assimilation of carbon dioxide, but also for growth and formative processes, as well as the nature of plant movements. In animals, exposure to light can also induce a number of vital reactions. This confirmed Beer's conclusion that there are a number of common features in relation to motor and other reactions in the functioning of the organism of plants and animals.

At one time, OP Dekaidol (1818) established that a mimosa plant "sleeping" in the dark can be "awakened" if it is suddenly exposed to light. Behr, returning to these experiments, confirmed the presence of such shifts in the physiological state of the plant. At the same time, he introduced an important clarification into the conclusions of Decandol, pointing out that the effect of "awakening" does not affect immediately. If the plant "awakened" by the light is immediately removed into darkness, the process of "awakening" continues, despite the removal of the external stimulus * that caused it.

*(Ibid., P. 262 - 272.)

Beer's report, named above, contains a lot of material on the effects of light on animals, including details of the color change of a chameleon, pathological abnormalities in visual ability in humans, etc. This material is mainly of an overview nature, but it testifies to an interesting fact: interest in color problems led Bera also to the consideration of a very specific and little-studied history of color codes in world literature.

Beer was always interested in color perception issues: as early as 1871, he conducted experiments with daphnia and some other invertebrates, establishing in them the usual in some cases "a series of decreasing color preferences: blue, green, yellow, red". Later, Bera was also attracted by studies of color blindness in connection with the identification of the causes of accidents on the railways *. However, the direct reason for Berm's study of human perception of colors, and in a historical aspect, was the book by the professor of ophthalmology in Breslau (Wroclaw) Hugo Magnus "The Historical Development of the Sense of Color". Studying the evidence of literary history, Magnus came to the paradoxical conclusion that not long before Homer, people did not even distinguish between red, green and yellow; in fact, their vision was black and white. As proof, Magnus referred to the private replacement in the Indian holy book "Rig-Veda" of the designation of red by white, as well as to the fact that Aristotle and other ancient Greek philosophers regard all colors as combinations of black and white **.

*(See: Bert P. Le daltonisme et les accidents de chemins de fer. - Rev. sci., 1871, vol. 2, p. 119-131.)

**(See: Magnus II. Die geschichtliche Entwickelung dcs Farbensinnes. Rostock, 1877.)

Analyzing this thesis, Behr traces the history of the question of color designation. At the same time, he refers to the works of L. Geiger (the predecessor of Magnus on the study of color designation among the ancient classics), as well as to the studies of the famous English politician W. Gladstone on the Iliad and Odyssey *, where it is proved that the designation of colors in Homer and other early authors are still very vague and confused. After evaluating all these considerations and comparing them with the results of his experiments on lower animals (and even plants), which in their own way unmistakably distinguish colors, Behr came to the conclusion that it is unlikely that human visual perceptions could change significantly over stories. “It is possible,” Ber wrote, “that (in the course of human history - Ed.) Prolonged exercises of attention, leading to a more perfect exercise of the retina and optic nerve centers, forced a person to distinguish in language and designate with different words sensations between which they initially did not notice differences "**.

*(See: W. Gladstone E. Homeric synchronism: an inquiry into the time and place of Homer. London, 1876.)

**(Bert P. L "evolution historique du sens de Ja couleur. - Rev. sci., 1879, vol. 1, p. 185.)

The merit of Beer's work in the field of the effect of color on plants, in comparison with the works of many subsequent authors, is obvious. He strove to pose the problem of the "perception" of color by a plant in a broad general biological context, as a special case of the problem of the interaction of a living being with color and light. In terms of the breadth of his approach to this problem, Bera can be compared, perhaps, only with Goethe *.

*(On the merits of Goethe, the great poet and natural scientist, in the field of the doctrine of color, see: I. Kanaev, Essays from the history of the physiology of color vision from antiquity to the 20th century. L .: Nauka, 1971, p. 45 - 58.)

The range of questions raised by Ber in one connection or another with observations of the plant organism is broadened. The scientist even expressed his attitude to the idea of ​​the effect of atmospheric electricity on plants, discovered in 1878 by Berthelot, Grando and Seli *. Behr did not consider the results obtained by these researchers convincing enough, and urged the staff of botanical gardens to further work in this direction. The versatility of Beer's botanical interests can be judged by his works published in "Revues scientifiques". Of these, we note: "The world of plants before the appearance of man" - an article dedicated to the presentation of the works of G. Saporta, one of the first Darwinist botanists and founders of modern paleobotany (vol. 1); "Insectivorous Plants" - a review of the works of F. Darwin, W. Kellermann and K. Raumer (vol. 2); "On the origin of cultivated plants" (v. 5); "Formation of nitrogenous substances in plants" (v. 7). Behr studied the effect of shaking and movement in general on the growth and reproduction of lower plants, mainly bacteria. Thus, he showed the harmful effect of various forms of "hyperdynamia" on the plant cell.

*(See: Bert P. L "electricite atmospherique et la vegetation, p. 300-303. Research on the effects of electricity (including atmospheric) remains relevant to this day, and has grown into a large independent field of research. For more see: The influence of some Cosmic and Geophysical Factors on the Earth's Biosphere), Moscow: Nauka, 1973, pp. 164 - 188, 195-199.)

On the question of the priority in obtaining these data, a controversy flared up between Ber and the Kiev scientist A. N. Horvat *, who underwent an internship in Strasbourg with the German professor L. de Bari. Ber's opponents tried in vain with her "help" to prevent Ber's election to the academy. As for the essence of the priority dispute, both sides were equally motivated: the research of Ber and Horvath was carried out almost simultaneously. Note also that Behr was one of the first to establish the presence of true vessels in arboreal fern-like plants.

*(See: Horvalh L. De l "influeuce du repos et du mouvements dans les phenomenes de la vie: Observations sur le role joue par M. Paul Bert. Paris, 1878.)

Beer's botanical work and his related historical, scientific and other studies were an essential aspect of his multifaceted scientific activity. And we can safely say that, for example, Beer's views on general biological issues would not have struck so much with their universality and validity (for his time) if the scientist had not illustrated them with plant science materials.

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Working with viruses in a medical laboratory, teaching in schools and universities, collaborating with museums, organizing research trips and expeditions - these are a wide range of activities of a biologist. It is quite natural that the profession of a biologist is closely related to science, because a person only cognizes all living things that surrounds him, and at the same time and quite pragmatically seeks to subordinate him to his will.

Biology work

What a biologist is doing is clear to everyone in general terms, while not everyone is ready to delve into in particular. That is why the uninitiated is little aware of the fact that a botanical scientist will not understand a molecular engineer, and combines them with one concept - biologists. But given the fact that there are different profile specializations, a biologist can be employed in a wide variety of areas of activity. Probably, he is better versed in the structure of cells, the structure of DNA and chemistry, so he works in a research center, or loves zoology, so he went on a long expedition to the Far North. Even the great biologists have never tried to grasp the immensity and have long specialized only in their narrow field.

So there are many places where a biologist can work. Perhaps, in the ordinary world, far from subtle matters and science, the biologist KDL is most in demand - an employee of the laboratory engaged in the study of analyzes of patients of various clinics. It is on the basis of his verdict that an objective diagnosis is made to the patient and treatment is prescribed. A biology teacher is another vacancy that a graduate of the biology faculty can get, in addition, highly qualified biologists are in demand as teachers in universities. The position of a biologist is also at industrial facilities, his task there is to monitor the level of pollution and the state of the environment of the city in which the enterprise is located.

At the same time, few people know about what a biologist does on hikes and expeditions. Its task is not only to study the composition of the region's fauna and flora, but also to establish, in close cooperation with ecologists, which phenomena harmful to nature and humans can occur in the area under study. Everything, from the chemical composition of tree sap to the size of the bird population, can tell them what kind of processes are taking place in a given region. This is especially important when studying protected areas where endangered species of animals live and rare plants grow.

Even Lomonosov, as a biologist, noticed that the slightest changes in biosystems can lead to irreparable consequences for entire regions, for example, the spread of a new species of weed plant did not allow getting the previous crop from the fields. Foreign and Russian biologists of the 20th century developed these ideas, in fact, founding a new science - ecology.

Biologist salary

English will be useful for biologists only when they, having sufficient knowledge, are ready to go abroad in search of better jobs and wages, those who work in the field of molecular biology are well received there. Then how much does a biologist earn in Moscow and the regions? Is the salary of a biologist in Russia acceptable to few?

Those who work in the provinces earn from 9 thousand rubles a month, in the capital a little more - from 12 thousand. In addition to salaries, the employees of the research institute are entitled to all kinds of grants and incentives from the state. Therefore, the requirements for a biologist, who is on the staff of research centers, are much higher than for workers in reserves, museums or industrial enterprises.

How to become a biologist

Everyone knows where to study as a biologist - at the biology department of any university specializing in the study of natural sciences. Educational institutions with biology faculties are open in all regions of Russia, and the biology specialty is considered a profession available for mastering the broad masses of the population. Professional retraining of biologists is also carried out by universities, as well as advanced training of biologists. In any case, in order to get the coveted diploma, you will have to try hard: after all, chemistry and molecular biology are not the easiest sciences.

Every person dreams of choosing a profession that would not only be always in demand, and therefore highly paid, but also benefit society. One of these professions is undoubtedly the profession of a biologist. It is these specialists who study everything related to living organisms on our planet. Our health, development and future largely depend on their professionalism. Therefore, it is not surprising that the biology profession is the second most popular in the world.

Every person dreams of choosing a profession that would not only be always in demand, and therefore highly paid, but also benefit society. One of these professions is undoubtedly biology profession... It is these specialists who study everything related to living organisms on our planet. Our health, development and future largely depend on their professionalism. Therefore, it is not surprising that the biology profession is the second most popular in the world.

True, unfortunately, not everyone can get this necessary and promising profession, since it puts forward a number of requirements that can only be met by people with certain inclinations and character. But what is the peculiarity of this profession, you will learn from our article.

Who is a biologist?

From Greek biology translated as "life science" (bios - life, logos - science). Accordingly, the name of the profession of a biologist indicates that this is a specialist who studies aspects of the life of all living organisms on planet Earth. That is, his close attention is drawn to the origin, evolution, growth and development of living organisms, regardless of whether it is a microbe, plant or animal.

Biology was officially separated into an independent branch of science only in the 19th century. However, its formation dates back to even more ancient times. It is known that already the great Aristotle in the 4th century BC. made the first attempts to streamline information about nature, highlighting four stages in it: people, animals, plants, the inorganic world.

Today, the profession of a biologist brings together specialists of very different specializations, each of whom is studying only a certain class of representatives of living organisms. For example, anatomists and physiologists study the structure and characteristics of human life, zoologists specialize in animal anatomy and physiology, and a botanist is engaged in the flora. And this is not a complete list of the biologist's specialization. There are also such modern trends as genetics, microbiology, biotechnology, embryology, breeding, biophysics, biochemistry, virology, etc.

But in any case, whatever specialization I choose biologist, his duties are almost identical. The duties of any biologist include: studying, systematizing, studying the general properties and patterns of development of a particular group of living organisms, conducting research in laboratory conditions, analyzing the results obtained and issuing practical recommendations for improving conditions within the framework of his specialization, etc.

What personal qualities should a biologist have?

It is not difficult to guess that a biologist, first of all, must love nature and be interested in the appearance and development of life on Earth. In addition, a true biologist is distinguished by:

• analytical and logical mindset;
• curiosity and patience;
• neatness and care;
• observation and rich imagination;
• well-developed figurative visual memory;
• perseverance and ability to concentrate;
• responsibility and honesty.

It should be noted that since biologist's job involves participation in laboratory research, in which various chemical preparations are often used, the specialist should not have a tendency to allergies.

The benefits of being a biologist

As mentioned above, biology is an actively developing branch of science that opens up huge prospects for career growth and self-realization for specialists. Another undoubted advantage of the biology profession is its relevance. According to labor market experts, this profession in the coming years may become one of the most demanded and highly paid ones.

An important advantage of this profession is also a wide variety of institutions and organizations in which you can show your talent and professional skills. Today biologists are gladly recruited in laboratories at research institutes, environmental organizations, nature reserves, botanical and ecological gardens, research institutes, environmental organizations, agriculture and education (schools, colleges, universities).

Disadvantages of the biology profession

Despite the fact that biology is one of the most demanded branches of science in the world, in Russia this field of activity is still at the stage of formation, so the salary of biologists is low. Especially if they work in government agencies (for example, in laboratories at research institutes or schools).

The work of a "practicing" biologist (a specialist who studies living organisms in their natural habitat) involves frequent business trips. These specialists can be found everywhere: in the desert, and in the tundra, and high in the mountains, and in the field and at an experimental agricultural station. Naturally, it is not always possible to conduct research in comfortable conditions, therefore, future biologists must be prepared for life in Spartan conditions.

For successful employment of young specialists, more often than not, theoretical training alone is not enough. So biology students it is necessary to take care of practical work experience in advance (that is, while still in the learning process, look for work in a specialty that is as close as possible to the future profession).

Where can you get the profession of biology?

It is very easy to acquire the profession of a biologist in Russia today, since almost every medical university has specialized faculties (biological, bioengineering, agronomic, etc.). Therefore, the choice of this or that university depends solely on personal interests and capabilities. Naturally, among universities there are also undoubted leaders, biology graduates who get high-paying jobs much more often than graduates of other educational institutions. Therefore, if you are interested in successful employment, we recommend that you, first of all, try to become a student of such universities as:

• Moscow State University M.V. Lomonosov - Faculty of Biology;
• Russian State Agrarian University - Moscow Agricultural Academy K.A. Timiryazeva - faculties: agronomic, soil science, zooengineering, agrochemistry and ecology, gardening and vegetable growing;
• St. Petersburg State University - Faculty of Biology and Soil Science;
• Moscow State University of Applied Biotechnology - faculties: automation of biotechnical systems and food biotechnology;
• Moscow State Academy of Veterinary Medicine and Biotechnology. K.I. Scriabin - faculties: zootechnology and agribusiness, veterinary and biological.

|Marina Emelianenko | 6501

One of the greatest books is the book of nature, but in it humanity has only read the first few pages.

We all live on planet Earth, about which we know a lot, but it still keeps a huge amount of secrets. Many are trying to solve them, but the greatest interest in the riddles of nature and man, their structure and functioning, interests people of such a profession as biologists.

Who is a biologist, what is his job?

What does a specialist like a biologist study and work on? This profession is multifaceted, it has a number of subspecies and varieties. A biologist is a person who studies and investigates the features and laws of origin and development of all living organisms, their interaction with each other, with the environment. There are various specializations into which the profession is subdivided:

Botanist - a specialist who studies plants, their properties, characteristics and differences;

Zoologist - explores the features of life, structure and functioning of animals, their types and classes;

Anatomist and physiologist - studies the structure and physiology of a person;

Geneticist - studies the features of the development of various species, heredity, variability, gene functions

Microbiologist - they study the internal structure of a cell, the characteristics of viruses and bacteria, ways of dealing with them;

Biophysicist and biochemist - investigate the physical and chemical processes occurring in organisms, without which their vital activity is impossible.

These are not all existing specializations, but they are the most widespread and well-known. In order to succeed in any of them, it is necessary to have a store of knowledge in all, since they are all interconnected with each other.

Work as a biologist. Pros and cons.

There are a number of advantages and disadvantages to working as a biologist, just like in any other profession. The main advantages include the following:

A fascinating and interesting work that will be relevant for a very long time, since even the human body has not been fully studied, not to mention the rest of nature;

A good prospect abroad, where this profession is of greater value and popularity than in our country.

Cons of the profession:

Low wages;

Long-term training and continuous self-education;

Low demand for the profession.

Personal and professional qualities that are needed to work as a biologist.

As with any profession, in order to become a highly qualified biologist, you must have certain professional and personal qualities, such as:

Love for nature and all living things. The main characteristic, without which the biology profession will not be enjoyable and will simply become impossible;

The presence of logical and analytical thinking. When conducting various experiments and experiments, in order to come to the correct conclusion, you will need a special mindset;

Good memory. Since a biologist works with a huge number of names and terms (not only in Russian, but also in Latin), this characteristic is also very important;

Purposefulness and perseverance. Often, when working with the smallest details, you have to be in one position for a long time, unable to even move;

Having creative and creative thinking. As in any profession, it is necessary to approach the tasks and work in general with enthusiasm and a good mood.

Biologist career and salary.

After receiving a specialized education, a biologist can find work in research centers and institutes. You can start moving up the career ladder while still a university student. To do this, you should prove yourself on the positive side and take part in research in the role of a laboratory assistant.

In addition, in this profession, everything depends on the person himself, his desire, dedication, since the specialty of a biologist does not have a specific career path. Salaries also vary depending on the place of work, the functions performed and the level of education.

It is important to note that it is relatively difficult to get a job as a biologist, but this is not due to the fact that the requirements are high, but to the fact that vacancies appear infrequently.

Where can you get a biology specialty.

In the subject of biology, education can be obtained at the following universities:

The work of a biologist is mainly mental, not physical, labor. This is the conduct of various experiments and experiments, the ability to plan and draw logical conclusions. Very often, biologists work not only in the office, but conduct their research directly in the field, which requires a certain amount of physical training and living skills.

Thus, the specialty of a biologist will be of interest to creative, active natures who strive to study the world around them and who want to make new discoveries.

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reference

Biology is the science of life in all its manifestations. It stood out from the natural sciences in the 19th century, when scientists began to notice that living organisms have some characteristics common to all. However, the origins of biology can be found in Ancient Greece, Rome, India and China. Aristotle in the IV century BC for the first time tried to streamline knowledge about nature, highlighting 4 stages in it: the inorganic world, plants, animals, people.

Today, practical developments of biologists are used in many areas: medicine, agriculture, industry and others.

Demand for the profession

Little in demand

Profession Biologist is considered not very popular, since the labor market is experiencing a decline in interest in this profession. Biologists lost their relevance to employers either due to the fact that the field of activity is becoming obsolete, or there are too many specialists.

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Description of activities

The biologist is engaged in research of flora and fauna of the Earth. He studies all aspects of the life of living organisms on the Earth, their structure, growth, development, origin, evolution and distribution around the planet. He classifies and describes living things, studies the interaction of species with each other. The activity of this scientist depends on his specialization. Botanists study the flora, zoologists - animals, anatomists and physiologists - the human body, microbiologists - unicellular organisms, and these are not all directions. In addition, he must have knowledge of chemistry, physics, ecology, medicine, as well as basic knowledge of the Latin language.

Most often, a biologist's working day takes place indoors: in a laboratory, clinic, in production. He collects the necessary materials, substances and material samples. Applying all kinds of devices and equipment, he conducts experiments and research, the results of which will be applied in a particular industry. In addition to laboratory work, it is possible to work in natural conditions and business trips to places where certain plant species and animal habitats grow. Sometimes it can be hard-to-reach areas with unusual natural conditions.

Wage

average for Russia:average in Moscow:average in St. Petersburg:

The uniqueness of the profession

Rare profession

Representatives of the profession Biologist really rare these days. Not everyone dares to become Biologist... There is a high demand for specialists in this field among employers, therefore the profession Biologist has the right to be called a rare profession.

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What education is needed

Two or more (two higher, additional vocational education, postgraduate studies, doctoral studies)

In order to work Biologist it is not enough to graduate from a university and receive a diploma of higher professional education. The future Biologist you need to additionally obtain a diploma of postgraduate professional education, i.e. complete graduate school, doctorate or internship.

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Labor responsibilities

The biologist develops and conducts laboratory experiments, experiments and research entrusted to him. For the experiment to take place, he must develop its plan, prepare the necessary materials and equipment. Observing the progress of the study, the biologist registers the readings of the instruments, makes the necessary changes. Then he analyzes the data obtained, writes a scientific report and submits it to the enterprise or companies that ordered this study. In the report, he should give practical recommendations for improving production conditions.

Like any scientist, a biologist must constantly improve his qualifications and introduce new technologies into his work, use modern equipment.

The duties of a biologist may include teaching if he is an employee of an educational institution.

Labor type

Predominantly mental work

Profession Biologist- This is a profession of predominantly mental work, which is more connected with the reception and processing of information. In work Biologist the results of his intellectual reflections are important. But, at the same time, physical labor is not excluded.

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Features of career growth

Biological specialists can find jobs in research institutes, conservation organizations, agriculture and food processing. They can teach biological disciplines in educational institutions.

A biologist's career development depends on his place of work, the quality of his duties and self-education.

Career opportunities

Minimum career opportunities

Based on the results of the survey, Biologists have minimal career opportunities. It does not depend at all on the person himself, just a profession Biologist does not have a career path.

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