page_title: Ivan Tarkhanov (physiologist)
section_title: Research
hierarchical_section_title: Ivan Tarkhanov (physiologist) / Research
caption_attribution_description: English: Tarkhanov's bust
context_page_description: Ivan Romanovich Tarkhanov or Ivane Tarkhnishvili was a Georgian physiologist and science populariser from the Tarkhan-Mouravi noble family. He led the Department of Physiology at the Academy of Military Medicine from 1877 to 1895 and authored a slew of articles on physiology for the Brockhaus and Efron Encyclopedic Dictionary. Among his numerous contributions was the discovery of the skin galvanic reflex. However, Tarkhnishvili's most significant contribution was the discovery of the influence of X-rays on the central nervous system, animal behavior, the heart and circulation, and embryonic development. Indeed, these works have given rise to a new field in science as Radiobiology.
context_section_description: Tarkhanov was interested in different fields of physiology. His greatest interest was in electrophysiology, which was a direct continuation of the work of I. M. Sechenov, of whom Tarkhanov was one of the first disciples. Tarkhanov engaged in experimental studies on the phenomena of summation in the nervous system (1869). He also studied the influence of compressed air, oxygen, and carbonic acid on nervous irritability (1876). He described the formation of bile pigments in animals and humans (1874) and was one of the first to show (1871) the restoration of fading functions in anemic animals by infusing saline in the body. He dominated work in the field of the physiology of aging (1891) and many other topics. Tarkhanov was one of the first to investigate hypnotic suggestion. Tarkhanov's books, Hypnotism, Suggestion and Mind-reading (1886; translated into French in 1891) and Suggestion and Hypnotism (1905) aroused wide public interest.
  In 1885 experiments on cutting and artificial emptying of the seminal vesicles, Tarkhanov showed that the latter played the crucial role in the generation of sexual excitement in frogs. Proceeding from these experimental results, Tarkhanov put forward a hypothesis that filling and evacuation of the seminal vesicles were the main biological cause which led to sexual arousal and its disappearance in mammals and humans.
  Tarkhanov is probably best known as a pioneer of psychophysiology and radiobiology. In 1889, he was the first to observe and document the psychogalvanic reflex, i.e., variations in skin electrical potentials in the absence of any external stimuli. Tarkhanov's method is still used today to measure skin potential. It records weak current actually produced
  by the body. Tarkhanov demonstrated that not only physical stimuli, but also mental activity, resulted in skin potential changes. The skin galvanic reflex is still used in applied psychophysiology as part of the polygraph in lie detection in which changes are recorded in several physiological variables while the subject is asked a series of questions pertaining to a specific issue under investigation.
  After irradiating frogs and insects with X-rays in early 1896, several weeks after Röntgen's discovery, Tarkhanov concluded that these newly discovered rays not only photograph, but also "affect the living function". These experiments signaled the birth of radiobiology.  Tarkhanov found a marked attenuation of excitability and a total suppression of acidic reflexes. These experiments confirmed that the impairment of reflexes after X-ray exposure depended on neither analgesia nor sensitive skin but on the moderating effect of the central nervous system (CNS) itself. Studying the effects of X-rays on metabolism in the myocardium and the circulation of the heart, he concluded that all of the effects of X-rays were due to their moderating or retarding the activity of the CNS (1896). A few years later, Tarkhanov presented an extensive paper on the role of X-rays in biology
  and medicine (1903). Thus, his pioneer works had indeed forecast a new field of science as radiobiology.
  Tarkhanov worked intensively at translating many medical and physiology textbooks, among them Technical Textbook of Histology, by L.-A. Ranvier (1876) and General Muscle and Nerve Physiology by I. Rosenthal (1879). Between the years 1892 and 1904, Tarkhanov contributed nearly 160 articles, from B to Z, in physiology and medicine to the Brockhaus and Efron Encyclopedic Dictionary. Following his resignation from the St. Petersburg Military Medical Academy, he published during the period 1897–1908 nearly 250 popular articles on a variety of topics. In these publications, Tarkhanov discussed many exciting problems of the time, such as health, hygiene, and nutrition of the people, issues of education of children and women, the organization of women's higher medical education in Russia, and radiation safety. He appears through his writings as a progressive humanist scholar, struggling for justice in all areas of public life and many others. His great capacity for work, whi
caption: The monument of Tarkhanov in front of Tbilisi Medical University
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