Mesencephalon and Polien G. Mezernitsky

MESENCEPHALON, midbrain, one of the divisions (the third) of the brain; it includes the cerebral peduncle and the corpora quadrigemina, lying between the diencephalon and the isthmus cerebri. It develops from the middle cerebral vesicle, the cavity of which, narrowing, turns into the cerebral aqueduct (Sylvian aqueduct), connecting the third and fourth ventricles. The cerebral peduncles are formed from the anterior wall of the vesicle, and the corpora quadrigemina from the posterior wall. In humans, as in other mammals, the mesencephalon is relatively large only during the period of embryonic development, and then gradually lags behind in growth and is concealed by the surrounding parts of the hemispheres; its length in an adult is about 1 cm, and the posterior (upper) surface is longer than the anterior (lower). The anterior part (cerebral peduncles) consists of two thick tracts connecting the pons Varolii with the hemispheres; this part is visible from the base of the brain, whereas the posterior surface is concealed under the lower surface of the occipital lobes of the cerebral hemispheres (see Cerebral peduncles, Corpora quadrigemina). MEZERNITSKY, Polien Grigorievich (born in 1878), professor, prominent physiotherapist. In 1901 he graduated from the natural science department of the St. Petersburg University and specialized in physiology and physiological chemistry in the laboratory of N. V. Vvedensky. In 1901, Mezernitsky wrote a candidate's thesis on liver oxidases. In 1902, he was elected a Villier scholar for a work on the synthetic formation of xanthine bodies in the animal organism. In 1906, he graduated from the Military Medical Academy

and was retained for three years for advanced training, working in the clinic of V. N. Sirotinin and in the laboratories of physiological chemistry and in the physiological institute. After defending his dissertation ("Xanthine Bases, Materials on the Question of Their Role in Atrophic Cirrhoses of the Liver", St. Petersburg, 1909), Mezernitsky received a three-year foreign travel grant. In 1910, at the invitation of the Society of Bad Kreuznach Physicians, he worked at a radium extraction factory. The work produced was reported at the International Congress of Radiology in Brussels and was awarded an apparatus for obtaining radium emanation. In addition, during his business trip, Mezernitsky produced and published a number of interesting works, one of which, emanating from the Curie laboratory and devoted to the decomposition of uric acid under the action of radium emanation, was reported at the Paris Academy of Sciences (18/III 1912). In 1913, Mezernitsky headed the therapeutic department and X-ray room of the Nikolaev Military Hospital. In 1920–1922, he was a professor at the faculty clinic of the Tiflis State University. In 1922–1925, a professor at the Baku University; in 1926–1927, a professor at the Tiflis University in the department of physiotherapy; in 1927–1931, director of the State Institute of Physiotherapy and Orthopedics of the People's Commissariat of Health (GIFO) in Moscow. Since 1927, Mezernitsky has been a professor of the department of physiotherapy and balneology at the 1st Moscow State University. Mezernitsky founded the following societies: Abastumani Physician-Therapists, Azerbaijani Physician-Therapists, and the Phenological Society in Crimea. Mezernitsky is a member of the editorial boards of the journals "Physiotherapy", "Tuberculosis Questions", and "Kurortnoe Delo". Mezernitsky serves as chairman of the Moscow Physiotherapy Society and vice-chairman of the All-Russian Association of Physiotherapists. Mezernitsky has published over 125 works, the most important of which were published as separate editions: "Radium and Its Application in the Therapeutic Clinic" (St. Petersburg, 1912), "Physiotherapy" (Leningrad, 1926). Under Mezernitsky's editorship, the first major collective textbook on physiotherapy in the Russian language was published (vol. I - Phototherapy, Petrograd, 1916). Mezernitsky is a pioneer of radiology in Russia. In recent years he has been developing issues related to the study of the mechanism of action of radiant energy, as well as the dosage and dosimetry of solar energy.