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Lazarev, Petr Petrovich

Lazarev, Petr Petrovich

(b. Moscow, Russia, 14 April 1878; d. Alma-Ata, U.S.S.R., 24 April 1942)

physics, biophysics, geophysics.

Lazarev’s father was a civil engineer. Upon graduation from the Gymnasium in Moscow, Lazarev entered the Medical Faculty of Moscow University, from which he graduated with distinction in 1901. In 1902 he passed the examinations for the academic degree of doctor of medicine and became an assistant in the ear clinic at Moscow University. Lazarev became deeply interested in the physical and mathematical sciences while he was still a student, and in 1903 he passed the examination for the entire course of study in the Faculty of Physics and Mathematics without ever having attended classes there.

While working in the ear clinic, Lazarev completed his first two research papers on the activity of the sensory organs. In the first paper he demonstrated experimentally that the phases of overtones do not influence the reception of sound. This helped to serve as an argument in favor of Helmholtz’resonance theory of hearing. In the second paper Lazarev demonstrated a distinct connection between auditory and visual sensations: the audibility of a sound is intensified by the simultaneous stimulation of the eyes by light.

In 1903-1905 Lazarev attended the weekly colloquiums of P. N. Lebedev and conducted several unofficial physical experiments in his laboratory. This work served to initiate a close friendship and scientific collaboration that lasted until Lebedev’s death in 1912. In 1907 Lazarev passed his masters examinations and became an assistant professor at the Faculty of Physics and Mathematics of Moscow University. In 1911 he defended his master’s dissertation on the temperature discontinuity at the gas-solid boundary. This topic, which arose from a research project conducted by Lebedev on the sensitivity of vacuum thermoelements, possessed great importance as a new experimental confirmation of the kinetic theory of gases. From that time on, Lazarev became Lebedev’s chief assistant and the independent head of a group of researchers concerned with molecular and chemical physics.

In 1912 Lazarev defended his doctoral dissertation, “Vytsvetanie krasok i pigmentov v vidiraora svete” (“The Fading of Colors and Pigments in Visible Light”). In this work Lazarev first established the connection between the quantity of matter decomposed under the influence of light and the light energy absorbed, as well as the dependence of the speed of a reaction upon the length of the light wave and the influence of oxygen on fading. This work, which is now acknowledged as one of the fundamental investigations of prequantum photochemistry, led to a series of investigations both abroad and in Russia.

In 1911 a significant number of professors and teachers left Moscow University as a protest against the reactionary actions of the minister of education, L. A. Kasso. Among them were Lazarev, Lebedev, and the majority of their colleagues. A short time later Lebedev’s laboratory work was transferred to a small private institution, Shanyavsky City University. After Lebedev’s death in April 1912, the supervision of his laboratory was entrusted to Lazarev. During the following years he began to concentrate his scientific interests on biophysics of the sense organs and the theory of nerve excitation. Guided by several experimental works of J. Loeb, Lazarev established his ion theory of nerve excitation. As a basis for his experimental law of excitation, Lazarev accepted Loeb’s formula C1/(C2 + b) = constant (where C1 is the concentration of ions which give rise to the excitation of nerves and muscles, C2 is the concentration of ions which depress this excitation, and b is a constant). In his theory Lazarev proceeded from the proposition that the coagulation of colloidal albuminous particles initiates the excitation process. The stability of the system is determined by the sign of the charge of the ions present in the solution. Lazarev produced many experimental research papers and, on the basis of extensive experimental material obtained by his collaborators, proposed the basic laws of ion theory for the excitation of living tissue. This theory has in significant measure retained its importance in modern biophysics.

Lazarev placed Loeb’s formula at the base not only of nerve and muscle excitation theory but of peripheral vision theory as well. Lazarev was one of the first to raise the question of the photochemical interpretation of the phenomena of eye adaptation, and he produced a series of works in support of this conception. In proposing that ions are the products of the photochemical decomposition of visual purple, Lazarev constructed the mathematical theory of the laws of peripheral vision under various conditions. He also formulated on these principles a theory of hearing and taste. Lazarev occupied himself with these questions for the rest of his life.

Lazarev’s activity was not limited to scientific research. From the beginning of World War I he participated in organizing medical aid for the front. He organized the production of medical thermometers, created the central diagnostic X-ray clinic for Moscow hospitals and a mobile X-ray section for the hospitals of the Moscow guberniya, and personally concerned himself with the training of physicians in roentgenology.

In 1917, shortly before the February Revolution, Lazarev was elected a full member of the Russian Academy of Sciences. He supported the October Revolution, and shortly afterward organized the first special scientific research institute for physics and biophysics in Russia. During the Civil War, Lazarev organized a laboratory in which he worked out the theoretical and practical problems of light and sound concealment and camouflage. In 1918 Lazarev, commissioned by the Soviet government, became the head of research into the Kursk Magnetic Anomaly. Before the Revolution, geomagnetic investigations in the region of the anomaly were conducted by E. J. Leyst. His investigations led him to suggest that enormous deposits of iron ore were to be found there, but geological prospecting did not support this view. The geomagnetic maps compiled by Leyst were stolen after his death.

Lazarev began all the work anew and established widespread geophysical and geological prospecting surveys which, in 1919, revealed the presence of enormous reserves of iron ore near the surface. He personally played a large part in implementing the geophysical calculations and initiated new investigations and geophysical methods of prospecting. He devoted much attention to scientific literature and was the founder of the journal Uspekhi fizicheskikh nauk.

BIBLIOGRAPHY

Many of Lazarev’s more than 500 published works are in Izbrannye sochinenia (“Selected Works”), vols. II and III (Moscow-Leningrad, 1950)—vol. I has not yet been published.

On Lazarev or his work, see the following (listed chronologically): E. V. Shpolsky, “Petr Petrovich Lazarev (1878-1942),” in Uspekhi fizicheskikh nauk. 27 no. 1 (1945), 1-12; T. P. Kravets, “Tvorchesky put akademika P.P . Lazareva” (“The Creative Path of Academician P. P. Lazarev”), ibid., 13-21; B. V. Deryagin, “O rabotakh akad. P.P. Lazareva v oblasti biologicheskoy fiziki” (“On the Works of Academician P. P. Lazarev in the Area of Biological Physics”), suppl. to Issledovania po adaptatsii P. P. Lazareva (“Studies in Adaptation by P. P. Lazarev;” Moscow-Leningrad, 1947); and S. V. Kravkov, “Petr Petrovich Lazarev (K desyatiletiyu so dnya smerti)” (“Petr Petrovich Lazarev “On the Tenth Anniversary of His Death””), in Uspekhi fizicheskikh nauk, 46 , no. 4 (1952), 441-449.

J. G. Dorfman

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