Neuropathology

NEUROPATHOLOGY, the doctrine of diseases of the nervous system. As an independent branch of medicine, neuropathology began to gradually separate from the middle of the 19th century; until that time, nervous diseases constituted only one chapter of psychiatry or internal medicine. It was precisely in Germany that this combination of neuropathology and internal medicine into one common discipline was delayed particularly long, whereas in most other countries, including Russia, neuropathology separated from related specialties comparatively early. Departments of neuropathology. Neuropathology divides into two main parts: 1) general neuropathology, dealing with the general questions of pathology of the nervous system, and 2) special neuropathology, dealing with individual clinical forms. The first department has always occupied a very prominent place in neuropathology; this is explained by the fact that general pathology usually leaves aside all animal processes. The second department was formerly subdivided, and sometimes is now subdivided, into the following subsections: the doctrine of diseases of the brain, of diseases of the spinal cord, of diseases of the peripheral nervous system, of diseases of the autonomic nervous system, and of neuroses. Such a division is however to a large extent conventional: many forms (for example, neurosyphilis, multiple sclerosis, syringomyelia, amyotrophic lateral sclerosis, etc.) often affect the brain and spinal cord simultaneously; others, such as lead poisoning, affect simultaneously the central and peripheral nervous systems, or, as in tabes dorsalis, the animal and autonomic nervous systems. It is thus impossible to clearly delineate diseases according to these groups. Therefore, attempts are now increasingly being made to divide neuropathology according to the etiological principle, separating it into departments dealing with toxic, infectious, traumatic, hereditary, etc., diseases, new growths, developmental anomalies, etc.—a division which is more correct. Many forms usually dealt with in neuropathology (epilepsy, traumatic neuroses, hysteria, neurasthenia, etc.) are simultaneously studied in psychiatry, and recently there has been a tendency to remove from clinical neuropathology the area of pure neuroses in connection with psychiatrists' approach to the problems of borderline states and so-called 'minor' (outpatient) psychiatry. Historical development of neuropathology. Modern neuropathology adheres to strict 'natural-physiological' thinking, and its development in all countries was inseparable from the progress of knowledge in the field of anatomy and physiology of the nervous system. However, it was precisely in brain anatomy that the purely morphological principle prevailed for a particularly long time. Various parts of the brain were described more or less accurately, without any explanation of the physiological significance of its topographical heterogeneity. Hence the nomenclature remaining from this epoch, in which only the external resemblance of one or another part of the brain to some known object was reflected. Thus were obtained the 'lyre of David', 'seahorse's foot', 'bird's spur', 'tree of life', 'olive', 'pyramid', etc., and only the apparent connection with physiologically known areas sometimes imposed on this terminology a certain as it were physiological imprint ('visual thalamus'), which however often proved to be erroneous. Thus the entire mass of the described brain and spinal cord appeared functionally still completely incomprehensible, as a result of which it was of course impossible to create a pathology of the nervous system. This period is well characterized by the following aphorism of Ranconi concerning the brain: 'Natura obscura, obscuriores morbi, functiones autem obscurissimae'. However, from the beginning of the 19th century, descriptions of facts began to arrive from all sides in favor of the observation that observations of the sick, on the one hand, and physiological experiments, on the other, could prove a certain functional division of various parts of the central nervous system. Charles Bell (Ch. Bell; 1811) precisely established such a fundamental fact of nervous physiology as the motor function of the anterior and sensory function of the posterior roots of the spinal cord. Subsequently, other authors made a series of outstanding researches that shed new light on the morphology of one or another part of the brain, which had seemed completely incomprehensible. Thus, in the 1840s, Brown-Séquard, through the most excellent experiments on animals and the correct interpretation of clinical-anatomical material from human pathology, established the unequal level of crossing of motor and sensory conductors in the spinal cord. However, these investigations at first concerned only the simplest, lowest functions, mainly the functions of sensitivity and movement. The more complex functions, especially as they concerned mental processes, of course could not yet be correctly delineated. However, the idea of the possibility of localizing mental functions long preceded the first precise works in this field; as is known, at the beginning of the 19th century F. Gall created an entire science, 'phrenology', which however was based on a false principle (the supposed protrusions of the skull over the most developed parts of the brain are said to indicate the development of this or that mental abilities) and was not based on precisely established facts. The failure of phrenology discredited for some time the doctrine of the localization of mental functions. Nevertheless, researchers of the first half of the 19th century constantly returned to this problem; the particular localization of speech functions in the brain began to be considered very probable, and finally in 1861 P. Broca (P. Broca) on the basis of the examination of two brains obtained from patients presenting the clinical picture of aphasia, could already quite precisely determine the area of the brain whose destruction makes the function of speech impossible. This area was determined precisely in the leg of the third left frontal convolution—a place which later received the name 'Broca's center'. This discovery, despite the fact that the absolute accuracy of the original determination is disputed by some contemporary authors, is rightly considered as having created an epoch in the study of the brain. A breach was made in the initial hypotheses about the functional homogeneity of all parts of the cerebral cortex. Indeed, in the 1860s and 1870s of the 19th century, the further doctrine of localizations began to develop rapidly. Followed one after another the discovery of excitability of motor centers (Fritsch, Hitzig), the brilliant clinical analysis of cortical convulsions (Jackson), the description of the sensory speech area (Wernicke), the syndrome of psychic blindness (Munk), etc. All these new views immediately began to penetrate into neurological clinic, which rapidly reorganized itself in accordance with new anatomophysiological data, which made possible the appearance in the 1870s-1880s of the brilliant constellation of such major neuropathologists-clinicians as Duchenne, Vulpian, Charcot with their numerous pupils (Erb, Remak, Friedreich, Wernicke, Jackson, Gowers, etc.). From the chaos of previously incomprehensible and confused nervous sufferings in this epoch such basic forms as tabes dorsalis, spastic paraplegia, progressive muscular atrophy with its various varieties, multiple sclerosis, amyotrophic lateral sclerosis, etc., were distinguished, and also the clear foundations of scientific electrodiagnosis were developed. In this process, the pathology of the spinal cord was studied particularly thoroughly, whereas systemic diseases of the brain as an organ, much less studied, long escaped attention. Instead, the attention of clinicians of this epoch constantly returned to hysteria, the great neurosis, which was still poorly diagnosed and which could give contractures, anesthesias and paralyses, externally somewhat similar to those which depend on organic lesions of the brain. As a result, a very great amount of work had to be done in the study of hysteria (Charcot, Gilles de la Tourrette, Bernheim, etc.) and to clarify the diagnosis between 'organic' and 'functional', which alone gave future researchers the possibility of the exact study of already known organic symptomatology. Of course, neuropathologists of this epoch could not remain pure clinicians. They inevitably had to be pathologists-anatomists and often to study the normal anatomy and histology of the brain. And indeed in the anatomical nomenclature of the brain we now constantly encounter the names of prominent clinicians (Monakow's bundle, Bekhterev's nucleus, Westphal-Edinger nucleus, Darkshevich's nucleus, etc.), and the pathological histology of the nervous system to this day has remained separated from general pathological-anatomical departments and institutes and is centered in special laboratories at neurological clinics and hospitals. This enormous and most fruitful clinical-anatomical work was made possible only because increasingly precise methods of histological research were developed simultaneously, which played a particularly important role in the development of clinical neuropathology and led to the spread of more correct views on the structure and mutual connection of the individual morphological elements of which the central nervous system consists. Indeed, precisely in the middle of the 19th century, the initial crude methods of studying the course of nerve fibers (hardening followed by mechanical splitting) were replaced by a more precise technique.

Stilling was the first to apply the method of dividing the spinal cord into a series of continuous sections, a method that allowed (especially thanks to a number of subsequent technical improvements) to approach much more closely the isolation of individual fiber systems and the establishment of their connection with one or another cell group; this became completely necessary after it was clarified (by Remak) that each nerve fiber originates from a nerve cell.--A significant step forward was also the replacement of the old carmine staining method (Gerlach) with hematoxylin staining (Weigert) and especially the introduction of the Golgi impregnation method, thanks to which it was possible to obtain much clearer pictures. Progress in this field of neurohistology led to the creation of the remarkable 'neuron theory' (Waldeyer). This theory was extremely valuable for the further development of clinical N. and formed the basis of all clinical-anatomical thinking of neuropathologists. According to this doctrine, the nervous system began to be conceived as the sum of histological nerve units, 'neurons' (a nerve cell with all its processes; some of which can be extremely elongated; axons, when separated from the nerve cell, undergo degeneration (secondary degeneration of Türk, analogous to Wallerian degeneration of peripheral nerve fibers), which allows one to trace the course of the entire degenerated system all the more clearly, since this degeneration, as it turned out, does not extend to the adjacent neuron. Thus, an extremely precise method of serial study of secondary (ascending and descending) degenerations was developed, by means of which our modern knowledge of the course of conducting pathways in the central nervous system was primarily obtained. The method of secondary degenerations was widely used in experiments on animals and in the pathological anatomy of humans.--Furthermore, Flechsig developed the embryological (myelogenetic) method of studying conducting systems, based on the asynchronous nature of their maturation. The comparative anatomical method also had great importance in this work. Thanks to all these methods, significant clarification was brought to the understanding of the function of individual components of the brain and spinal cord, which by this time ceased to be a mysterious organ with completely incomprehensible topography of gray and white matter, and was conceived as a very complex combination of centrifugal, centripetal, and associative systems, each of which has a very specific functional value. Therefore, clinical diagnosis also moved toward creating a semiotics not of this or that gross division of the brain and spinal cord_gbut of specific centers and systems and even more specifically of certain neurons from which these systems are composed. The epoch of this brilliant development of N. in the second half of the 19th century coincided with the establishment of the first independent neurological clinics and hospitals. The neurological clinic of the University of Paris, located in the Salpêtrière Hospital and headed by Charcot at that time, became particularly famous. A center of scientific N. formed in the Salpêtrière, which had world significance for a long period. Special neurological societies began to emerge (one of the oldest is the Paris Neurological Society, as well as the Moscow Society of Neuropathologists and Psychiatrists), journals (Revue neurologique, Deutsche Zeitschrift für Nervenheilkunde, Neurologisches Zentralblatt, Brain) and congresses began to be organized. The development of N. in Russia proceeded in parallel with the general development of N. The first clinic for nervous diseases was organized in 1869 by A. Ya. Kozhevnikov in the Novo-Yekaterininskaya Hospital at the first department of nervous diseases of Moscow University. Then in 1881, a neurological clinic (as part of the psychiatric clinic) was established at the Military Medical Academy by I. P. Merezhovsky in Petersburg. Leningrad and Moscow have since remained centers of Russian N., the two main schools from which a whole number of outstanding scientists emerged. The Moscow center was represented by a number of major students of A. Ya. Kozhevnikov (S. S. Korsakov, V. K. Rot, G. I. Pribytkov, V. A. Muratov, P. A. Preobrazhensky, G. I. Rossolimo, L. S. Minor, L. O. Darkshevich). Having moved his activities to Kazan, the latter created a branch of his school there with numerous students (A. O. Favorsky in Kazan, I. E. Osokin in Saratov, Pervushin in Perm, etc.). The Leningrad center produced a number of students of I. P. Merezhovsky as professors of provincial universities [V. R. Chizh (Yuryev), I. V. Sikorsky (Kiev), Ya. A. Antimov (Tomsk, Kharkov), A. E. Shcherbak (Warsaw), etc.]. V. M. Bekhterev, after Merezhovsky, was for a long time the head of the Leningrad school. As universities grew and neurological clinics were established at them, larger or smaller provincial neurological centers began to form, of which the following deserve mention: Kiev (P. N. Lapinsky and his school), Odessa (N. M. Potsov, Raipist, Yanishevsky, Markan, etc.), Kharkov (P. I. Kovalsky, now A. I. Geymanovich and A. M. Grinstein), Rostov-on-Don (K. S. Agadzhanian, now Emdin), Minsk (M. B. Krol), Tomsk (L. I. Omorokov), Tashkent (A. M. Kharchenko), Baku, Tiflis, etc. In Leningrad, L. V. Blumenau, M. I. Astvatsaturov, M. P. Nikitin, Gerver, etc., are currently working, while in Moscow—L. S. Minor, Ye. K. Sepp, V. V. Kramer, M. S. Margulis, V. K. Khoroshko, S. N. Davidenkov and others. Among the periodicals, the Moscow 'Journal of Neuropathology and Psychiatry', published since 1901, and the Leningrad 'Review of Psychiatry, Neurology and Experimental Psychology', published in 1926-30, played a particularly large role in our country. In Kiev, 'Contemporary Psychoneurology' has been published since 1925. In 1883-99, the 'Bulletin of Clinical and Forensic Psychiatry and Neurology' was published in Petersburg. A number of journals devoted to N. were founded in various scientific centers, but did not last until the present time. Among them, the most important were 'Questions of Neuropsychiatric Medicine', published in Kiev in 1896-1905, the 'Neurological Bulletin', published in Kazan in 1893-1918, the 'Psychiatric Gazette', published in Petersburg in 1910, and the 'Journal of Psychology, Neurology and Psychiatry', published in Moscow in 1922-24. A significant part of the work of Soviet neuropathologists is published either in the general medical press, or in special non-periodic collections and proceedings published from many clinics and institutes, or finally abroad, mainly in the German press. Due to this scattered nature, a complete account of Russian neurological literature has always been very difficult. While our neurological departments constantly sought to separate themselves from psychiatric departments, journals both in the past and now unite neuropathologists and psychiatrists.--The same applies to special congresses, which were periodically convened starting from 1887, when the I Congress of Domestic Psychiatrists took place in Moscow; the II Congress was convened in Kiev in 1905, and the III-in Leningrad in 1909. In 1911, the I Congress of the Russian Union of Psychiatrists and Neuropathologists took place in Moscow, and in 1927, the I All-Union Congress of Neuropathologists and Psychiatrists was held in Moscow. In addition, neuropathologists gathered at special sections of the Pirogov congresses and special meetings during the war and in the first years of the revolution and after the October Revolution. A major step forward compared to previous congresses in terms of the methodological review of psychoneurological disciplines and in particular clinical neuropathology was the Leningrad Congress on the Study of Human Behavior (1930). The development of problems in neuropathology based on Marxist-Leninian theory is dedicated to the activity of the Psychoneurologists' Society - Materialists at the Komakademy, as well as the Moscow Society of Neuropathologists and Psychiatrists, reorganized in 1929. This methodological review makes it possible to discard from neuropathology a whole series of vulgar-mechanistic or idealistic hypotheses and viewpoints that uniquely reflect class relations in bourgeois countries, and contributes to the reconstruction of Soviet neuropathology_twhich is necessarily connected with the era of socialist construction. Modern N. It can be considered that during the last quarter of the 19th century, N. had already completed its separation as a fully independent medical discipline. After that, its rapid progressive development does not cease, in which on the one hand, there is a greater development of further specialization within N. itself, and on the other hand, an increasingly closer connection of N. with other medical disciplines from which it was necessarily somewhat isolated during its initial constructive period. The main stages of this modern evolution of N. come down to the following. The connection of N. with the clinic of internal diseases becomes significantly closer each year.

Here, on the one hand, neurological syndromes resulting from general diseases and disorders of general metabolism are beginning to be studied in ever greater depth, such as funicular myelitis developing in pernicious anemia, nervous syndromes in so-called genuine hypertension, in polycythemia, uremic and diabetic nervous syndromes, neurological symptom complexes in general infections and toxicoses, etc.; on the other hand, attention is being focused on the questions of the relationship between general metabolism and the metabolism of the nervous system, which leads to the posing of the problem of the blood-brain barrier (see Barrier function). The in-depth study of the chemistry of cerebrospinal fluid is successfully incorporated into this circle of research. This work has already yielded a number of most interesting facts for understanding many questions of the general pathology of the central nervous system. - Further, in the direction of connecting neurological and internal medicine, questions related to the study of endocrine and autonomic functions have sharply come to the forefront. The main endocrine-nervous syndromes already identified (acromegaly, myxedema, hyperthyroidism) were quickly supplemented by a number of newly studied forms, while the initial simpler concept of the elementary connection of certain syndromes with one or another gland was gradually replaced by the concept of complex pluriglandular correlations. - Extremely fruitful for clinical Neuropathology have been the modern achievements in the field of the autonomic nervous system, especially in that part concerning the anatomy and physiology of the autonomic innervation of the coverings (vasomotor, trophic, pilomotor and sweating functions), a part already directly applicable to topodiagnosis (works of A. Thomas and others), thanks to which at the present time a whole new chapter in neurological clinic is being intensively developed. Likewise, the modern doctrine of the autonomic innervation of striated muscle fiber has made it possible to view the pathogenesis of such pathological processes as dystrophia musculorum progressiva, familial periodic paralysis and some forms of post-traumatic muscular atrophy in a completely new light. As is known, the change in our views on the pathogenesis of these forms has already led to new therapeutic attempts in this area, built more rationally. The last decade has also been marked by the rapid development of the very complex anatomy of the autonomic centers of the intermediate brain, - a chapter which is far from being completed, but already promises in the near future to make possible new and most interesting clinical-anatomical constructions. Similar to this diverse contact with different departments of internal medicine, increasingly profound connections of Neuropathology with other medical disciplines were also established. The most fruitful here was the contact with Neuropathological surgery ('neurosurgery'), revealing operative possibilities immeasurably broader than could have been assumed even recently, and giving actual interest to many localizations which formerly seemed to have only purely theoretical significance. Precisely in connection with the development of neurosurgery, the modern doctrine of tumors of the brain and spinal cord has developed rapidly. This development of the neurosurgical direction of Neuropathology is also indebted to the introduction of such most valuable methods of clinical research as contrast radiography with the introduction of air or lipiodol, which has quickly become a necessary moment in many complex diagnoses. Since the nervous system functionally participates in any system of organs, it is not surprising that Neuropathology is making contact with a number of other medical specialties. It is especially important to note the current significance of the contact with ophthalmology and otorhinolaryngology, which has already led in Western Europe and in the USSR to the appearance of special 'otoneuro-ophthalmological' scientific groupings. - Along with the development of such border specializations, within Neuropathology itself increasingly differentiated small specialties are gradually forming, requiring independent study. Such is, for example, pediatric neuropathology, containing so many peculiarities that it may seem advisable to single out a special specialization of 'microneuropathology' or 'neuropediatrics'. Finally, in this striving to abandon the initial isolation and to connect with all other questions of pathology, the doctrine of nervous diseases has again approached its old connection with psychiatry. If formerly, in the era of developing its own methods, the progress of Neuropathology required its separation from the clinic of mental diseases, now, on the contrary, armed with proven methods, neuropathologists are seeking ever closer rapprochement with psychiatrists. A more detailed study of the patient's psyche is becoming increasingly necessary for the neuropathologist. It is interesting that it is precisely from neurological clinics that attempts originated to give methodological schemes for psychological research ('psychological profile' of Rossolimo). This rapprochement of the activities of neuropathologists and psychiatrists is explained by both the commonality of many forms studied here (epilepsy, neuroses, many organic diseases of the brain) and the commonality of theoretical tasks facing the neuropathologist and psychiatrist (the study of higher nervous activity) and finally by the circumstance that in studying forms in terms of their social significance (questions of professional selection, disability, examination, exo- and endogenous moments in etiology, etc.), the work of neuropathologists and psychiatrists is for the most part inseparable. Thus, the question of the general basic specialization of the physician - 'psychoneurologist' - is gradually being raised again, however, usually with a certain bias in one direction or another (pathohistology, professional pathology, experimental neuropathology, genetics, etc.). In addition to the moments listed above, another determining factor in the development of modern Neuropathology has been the numerous achievements in the field of research methods, anatomy, physiology and general pathology of the nervous system. Of the research methods that have enriched Neuropathology in recent times, special mention should be made of the significant progress in radiography, the technique for studying the vestibular apparatus, as well as the introduction of the chronaximetry method. Among the new anatomical data, great importance is attached to works on somatotopic localization in the cerebellum, on the topography of arterial basins and especially works on the so-called extrapyramidal motor ('striatal') system. This last system, the pathology of which was first studied in 1911-12 by Wilson in progressive lenticular atrophy, by Foht and Oppenheim in double athetosis, and by Alzheimer in Huntington's chorea, proved to be extremely vulnerable in epidemic encephalitis, giving unexpectedly such a large number of new facts that at the congress of French neuropathologists in 1922 they rightly spoke of a real 'neurological revolution'. Indeed, taking into account the new data led to the need for a radical revision of our former concepts of the interaction of various brain systems, as a result of which a new interpretation of many previously known syndromes appeared. In particular, the study of the striatal system gave a strong impetus to the revision and more precise classification of the numerous hyperkineses playing such a large role in the clinic of diseases of the nervous system. At the same time, the area of 'functional' diseases has also sharply narrowed, in which until recently such diseases as chorea, paralysis agitans, myoclonias, many types of localized convulsions and tics, etc., were included. - Another important achievement of modern brain anatomy has been the histological study of the peculiarities in the structure of different zones of the brain (myelo- and especially cyto-architectonics) - works of Brodmann, S. and O. Fohts, Economo, which quickly showed that the boundaries of functionally identical parts of the cortex coincide precisely with these cytoarchitectonic fields, and not with the grooves and convolutions visible on the surface of the hemispheres; a viewpoint which again required a revision of our habitual topographic views. In the field of experimental physiology, recent times have been characterized by significantly greater clarification of laboratory facts, and above all by a more real possibility of building analogies between clinical syndromes and laboratory data. This is explained to a large extent by the fact that, experimenting with the brain, they began (Magnus, de Kleijn and their school) in extirpation of brain parts to proceed from the analysis of preserved functions to judge the physiological role of the preserved parts of the nervous system, instead of, as former experimenters did, attributing the lost functions to the extirpated part; thus, work with the brain became a direct continuation of the works of Sherrington and his school on the function of the isolated spinal cord. This method in conjunction with the greatest care in experiments has already brilliantly resolved a number of problems related to central regulation of tonus (see Decerebration). All these achievements have quickly found their reflection in the clinic of nervous diseases.

Thus, an analogy was established between the protective reflexes of humans and the reflexes of spinal automatism in Sherrington's experiments (Marie, Foix); detailed study began of human cervical, labyrinthine, and more complex stem reflexes, postural reflexes, induced movements, etc. The clinical material studied in this way is no longer isolated from the data of physiological laboratories and must serve as direct proof of the similarities and differences that exist between the human central nervous system and that of higher animals. Perhaps of even greater significance for the clinic of nervous diseases than the work of English and Dutch physiologists are the works of I. P. Pavlov and his school, which made it possible to more deeply penetrate the mechanisms of temporary connections constantly forming in the brain, and thereby provided the most convincing proof of the regular fluidity of states of excitation and inhibition in nerve centers. These principles have forced neuropathologists to largely abandon the once fashionable 'linear' schemes (like the well-known aphasic scheme of Lichtheim-Wernicke) that supposedly explained complex neuropsychic processes. The doctrine of conditioned reflexes has thus significantly contributed to the spread in neuropathology of a more correct physiological understanding and made neurological thinking much more dynamic. Moreover, the method of conditioned and combined motor reflexes was directly transferred to the neurological clinic. - Finally, in the course of clarifying the basic questions of general pathology, modern neuropathology is faced with the problems of the spread of poisons in the nervous system and their fixation, the theory of the selective action of poisons, the theory of patoclyses of O. Foht and a number of other basic pathological problems, testifying to the fact that modern neuropathology is most closely connected with all the basic questions of pathology. Thus, the period experienced by modern neuropathology could be defined as a period of extensive growth along lines bordering on related disciplines. This tendency extremely expands the boundaries of the basic discipline, making it much broader and more interesting, provides more solid biological bases for neurological thinking, and connects neuropathology ever more closely with the general philosophy of natural science, but at the same time forces individual workers in the field of neuropathology 48!) to specialize in narrower branches of it. It is completely natural that in this period of extensive growth, neuropathology had to approach the broadest questions of social significance. First and foremost among these are questions of etiology, which are now persistently being brought to the forefront, as they are directly connected with the tasks of prevention. Great achievements must be noted in the study of exogenous harmful factors (poisonings, injuries, acute and chronic infections), as well as in the questions of early diagnosis, which are acquiring great importance in connection with the introduction of methods of population dispensary care. It can be said that at present only a small number of pathological processes remain whose etiology is still obscure (such as lateral amyotrophic sclerosis), and this etiological study is characterized above all by the last quarter of the 19th century.-The study of professional factors in the etiology of diseases of the nervous system acquires special importance. Besides professional diseases in the narrow sense of the word (lead, mercury, arsenic, carbon monoxide and other industrial neurotoxicoses, writer's cramp and other professional dyskinesias, caisson disease, miner's nystagmus, acute and chronic professional neuritis, neuralgia, myositis and muscular atrophies), the role of professional harmful factors is being intensively studied as additional causes contributing to the manifestation or more severe course of other, essentially non-professional diseases of the nervous system. Such is the role of professional factors in the genesis of cerebral arteriosclerosis, thoracic outlet syndrome, etc. The achievements of professional neuropathology have already manifested themselves in practice in the reduction of professional diseases in a number of professions. Thus, we now almost never see the severe lead paralyses or carbon disulfide poisonings that were described in the textbooks of the 19th century. The study of professional etiological factors is now being intensively pursued by neuropathologists of all civilized countries, especially countries with rapid industrial growth. Naturally, in the Soviet Union, in connection with the turn of neuropathology to the practice of socialist construction, these questions acquire particular importance. And indeed in the USSR professional neuropathology is developing by leaps and bounds. A great deal of work is being done in this direction by the neurological departments of institutes for the study of professional diseases, as well as by neuropsychiatric dispensaries. Before professional neuropathology, besides the study of professional diseases, there stand a number of other, practically very important tasks: establishing norms and indications for professional selection and professional consultation, developing necessary preventive measures in the dispensary detection of initial forms, developing methods of neurological examination of various professional groups, studying the conditions of labor and daily life from the point of view of the harmful factors contained in them for nervous health, but also the study of the health-improving influence of labor, especially insofar as it is connected with conscious creative and construction work and is combined! with positively colored emotions, which unusually come to the forefront precisely in the conditions of the socialist construction we are experiencing; further- development of the details of neurological examination and determination of disability, statistical and demographic study of nervous diseases, etc. Since the development of all these questions requires besides knowledge of the clinic. also a number of quite special knowledge, a special type of specialization is gradually being developed - that of a physician-psychoneurologist with a bias toward professional pathology and social hygiene. Another front, along which the doctrine of the etiology of nervous diseases has begun to unfold in recent times, is the group of so-called endogenous factors, all the more important as it is precisely neuropathology that abounds in numerous forms that are either clearly hereditary or such in the origin of which hereditary predisposing factors are given a definite and significant etiological role. The first group includes numerous forms of hereditary muscular atrophies, all familial ataxias, amaurotic idiocy of Tay-Sachs and its varieties, familial spastic paralyses, familial striary syndromes, epilepsy, migraine, many trophoneuroses, etc. The second includes such forms as syringomyelia, peripheral paralysis of the facial nerve, vestibular angioneuroses pi pr. The analysis of hereditary regularities, as well as the correct nosography, built on the held clinical-genetic principle, is far from finished in either group. These topics are currently in neuropathology the subject of intensive study. In regard to those severe forms in which in case of risk of having sick offspring the advice to abstain from procreation is applicable, neuropathology aims to develop precise bases for correct medical-eugenic advice to sick and healthy members of the affected family. In regard to milder forms, the main intention is above all the necessity to place hereditarily predisposed subjects in conditions free from special harmful factors threatening the most vulnerable parts of the nervous system; the preventive question is thus transferred here to the sphere of organization of labor and daily life and above all to the sphere of professional selection, in which hereditary-constitutional data must now be taken into account. Thus the study of both exogenous and endogenous harmful factors directly concerns the tasks of social prevention, thanks to which these departments receive in modern neuropathology such powerful development. The teaching of neuropathology in most countries has been separated into an independent department with its own clinic of nervous diseases; and only in Germany does the connection of neuropathology with the clinic of internal diseases still remain very widespread. In our country until recently it was not uncommon to have combined departments of neuropathology and psychiatry, but at present the division of departments has already taken place in all medical institutes. At present, before Soviet neuropathology stands the question of creating new cadres, trained in the spirit of mastering neuropathology on the basis of dialectical materialism and Marxist-Leninin theory. In this sense, both the improvement of physicians and the reform of teaching in medical institutes are taking place. Neuropathology is taught by a laboratory method according to a new plan, in the 3rd or 4th year, for which 80 to 90 hours are allotted (not counting practice in the dispensary). The creation of psychoneurological departments in the therapeutic-prophylactic faculties is projected. With the growth of institutes for the improvement of physicians, clinics of nervous diseases are beginning to be organized there in the same way. Scientific research work in neuropathology, formerly concentrated almost exclusively around university departments, has begun to shift in recent years.

On the one hand, the large nervous disease departments of hospitals are increasingly acquiring the significance of scientific centers, on the other hand, scientific work is beginning to move into special research institutes (Psycho-neurological Academy and Reflexology Institute in Leningrad, institutes for the study of higher nervous activity, for the study of the brain and neuropsychiatric prevention in Moscow, Psycho-neurological Institute in Kharkov), as well as into nervous departments of institutes devoted to the study of related disciplines (physiotherapy, traumatology, neurosurgery, social medicine, genetics, etc.).