As we pointed out above, the most important feature of the Soviet science of anatomy is its dynamic aspect, i.e. it does not passively contem­plate and describe the body's structure, but endeavors to discover the regula­rities in the organism's structure and development and to control and direct the favourable and harmonious development of the human organism. The social factors responsible for increased individual variability of human beings have a direct effect on their physical structures. According to the theory of dialectical materialism, labour is the most important social factor affecting the structure and development of the human organism. When a man uses a tool, it is as if he has acquired a new organ that alters his ana­tomical structure. Anatomy is therefore always faced with the task of stu­dying exactly how man's tools affect his normal structure by complementing the natural tools of his body, i.e. the organs. Modern anatomy thus studies the anatomy of individuals, considering their living and working conditions and looking for the effect different types of work, i.e. occupations, have on the structure of the human body. Human anatomy under different occupational conditions (both work and sports) is a new branch of modern anatomy and is being developed at the Department of Normal Anatomy of the First Leningrad Medical Institute. This work was started on the initiative of M. G. Prives and has been continued for more than 25 -years by his colleagues. As the result of this trend, anatomy has become a dynamic science. This is illustrated in the sections "The Skeletal Structure of Various Occupational Groups" and "The Skeletal Structure of Athletes Engaged in Various Sports". Here are a few more illustrations. X-rays of the foot bones of a ballerina taken over a period of twenty years reveal the following. Work hypertrophy of the metatarsals developed when she began dancing, but atrophy appeared when she ceased dancing and became a dancing teacher; the bones acquired the same structure they had before she started dancing. Similar changes were found in the metacarpals of blacksmiths when some of their manual operations were automated. Con­sequently, changes in occupation or in the nature of a particular job, changes in the degree of physical exertion connected with various types of work and sports, and changes in different sports training programmes can have a direct effect on bone shape and structure. For all its hardness and "petrifaction" bone is a living organ, which continuously reorganizes and changes depending on the degree of physical exertion during movement, work, and other activities. The study of anatomy of people engaged in different occupations re­veals definite patterns of the development of changes in the bones. Thus ana­tomical science may help to control and direct bone development. The above illustrations of changes in bone structure directly induced by physical loads of varying weight demonstrate that anatomy can be useful. Thus, research involving people from different occupations and ath­letes engaged in different sports as well as studies of the X-rays of the same individual over a period of ten or twenty years have enabled us to identify the following definite patterns. The increased physical exertion directly associated with a particu lar occupation or sport causes work hypertrophy of the bones. Conversely, the compact substance of bones that are little used atrophies within normal levels. The hypertrophy develops specifically in those bones and parts of bones that receive the heaviest load. By choosing the physical load necessary for a given condition, one can influence bone structure in a desired direction. This is the principal feature of modern anatomy, namely its applicabi­lity, which makes deliberate regulation of the structure of bones possible. 4. Such regulation is of practical importance in planning working conditions and sports programmes, in preventing harmful effects from indus- trial occupational hazards, in the proper training of athletes, and in the proper physical training of schoolchildren. Thus, Goethe's definition of morphology as a science of structure, for­mation, and reorganization is becoming a reality. Description of the body structure comprises the descriptive feature of anatomy. The formation of structures makes up its evolutionary and functional features. And reorga­nization indicates the applicability of anatomy.