Gasser, Herbert Spencer

(b. Platteville, Wisconsin, 5 July 1888; d. New York, N.Y. 11 may 1963)

physiology.

Gasser’s father, Herman, was born in the Tyrol and emigrated as a boy to the United States, where he became a country doctor. His mother, Jane Elizabeth Griswold, came from an old Connecticut family. She trained as a teacher in the state Normal School of Platteville, which Gasser himself later attended. The controversies of the time concerning evolution, vitalism. and mechanism had led his father to acquire the works of Darwin, Huxley, and Herbert Spencer, which the younger Gasser read avidly. He entered the University of Wisconsin to major in zoology. Having completed quickly the requirements for a B.A. degree, he took courses in the newly organized medical school, where he first met Joseph Erlanger, with whom he was later to share the Nobel Prize. As the university was then only a half-school (two years) Gasser transferred to Johns Hopkins University, where the approach to medicine exactly suited his aims. Gasser’s professional Career was, in time, to involve him in teaching and administration as well as research. His other major interests were music, history, literature, and travel. His positions included instructor at the University of Wisconsin (1911–1916); physiologist at Washington University, St. Louis (1916–1921); pharmacologist in the Chemical Warfare Service (1918); professor of pharmacology at Washington University, St. Louis (1921–1931); professor of physiology at Cornell University Medical College (1931 1935); and director of the Rockefeller Institute for Medical Research (1935–1953). On retirement he continued active research for nearly ten years. From 1923 to 1925 Gasser was in Europe working with A. V. Hill at University College, London; Sir Henry Dale at the National Institute for Medical Research; Walter Straub at Munich; and Louis Lapicque at the Sorbonne.

Gasser received academic honors from many universities both in the United States and Europe. He was a member of the National Academy of Sciences, the American Philosophical Society, and a number of professional societies. In 1944, Gasser and Erlanger were awarded the Nobel Prize for discoveries relating to nerve fibers, and in 1945 the Association of American Physicians awarded Gasser its Kober Medal.

Gasser’s early work, dictated by the exigencies of World War I, was concerned largely with problems of traumatic shock and blood volume. Only after the war did his first work on nerves, written with H. S. Newcomer, appear. It concerned application of thermionic vacuum tubes to the study of nerve action currents. Then came the pioneering study, in association with Erlanger, on use of the cathode-ray oscilloscope as an inertialess instrument for recording action potentials of nerve and the initial analysis of their compound nature. Some problems arising at that time stayed with Gasser only to be resolved finally in his last paper, published in 1960. It is difficult in the days of near-universal television to imagine the early difficulties of oscillographic recording. Light intensity was so low that many repetitions of the nerve response were required to produce a photographic image, and tubes lasted but a few hours. Some consequences of these necessities were from one point of view essentially artifactual in nature. Typically, Gasser always was aware of, and concerned with, the possibilities of artifact. When it became possible to record single responses, it was apparent that they differed from those recorded during repetitive activity. A clue to the difference was found in subsequent study of the subnormal state of nerve which, by responding repetitively, had influenced the early recordings.

Major problems that commanded Gasser’s attention were the compound nature of the nerve action potential; the relation between nerve-fiber size and inpulse-conduction velocity; the excitability of nerve fibers in relation to after-potentials; potentials recordable form the spinal cord; the afferent fibers concerned with pain-producing impulses; and the morphology of unmyelinated fibers, with respect to their compound action potential and diametervelocity relations.

Some of these studies were direct offshoots from prior work, while others represented an abrupt change in direction or a return to old problems still unsolved, for Gasser espoused the principle that there are two times for working on a problem—before anyone has thought of it and after everyone else has left it. As a result, Gasser was always the innovator or the finalist.

At the height of the controversy over which types of nerve fibers yield various compound action potentials, Gasser turned to the question of after-potentials and associated excitability changes. His studies showed the after-potentials and the excitability states associated with them to be closely correlated, but different in the several groups of nerve fibers. This proved crucial to the characterization of fiber groups, for by this means some somatic fibers and sympathetic preganglionic fibers overlapping in diameter and conduction velocity could be distinguished, as could be the somatic and sympathetic unmyelinated fibers.

Whenever possible, Gasser required that the results of two approaches to the same problem be congruent. A prime example is the convergent information from electron microscopy and oscilloscopic recording that he achieved virtually single-handedly with respect to unmyelinated nerve fibers. He, however, found minor incongruity between the division of somatic afferent myelinated fibers (A fibers) into the subgroups α, β, γ, δ.recorded as elevations in the electrical response and the action potential reconstructed from anatomical fiber-size maps of the nerve made on the assumption that velocity varied in direct proportion to the diameter of the fiber. Unsatisfied, he finally identified the incongruity as a product of the method of leading from active nerve. Correcting this, he found that the potential of the skin nerve manifested but two elevations, α and δ. He wrote in his last published work, “Thus the action potential was brought into closer accord with the indications in the maps of fiber diameters.” Characteristically, this remark was an understatement.

BIBLIOGRAPHY

A complete bibliography is included in Gasser’s “An Autobiographical Memoir,” with a preface by J. C. Hinsey, in Experimental Neurology, supp. 1 (1964), and in Electrical Signs of Nervous Activity, 2nd ed. (Philadelphia, 1969), written with J. Erlanger.

David P. C. Lloyd

GASSER, HERBERT SPENCER

GASSER, HERBERT SPENCER (1888–1963), U.S. neurophysiologist and Nobel Prize winner. Gasser was born in Platteville, Wisconsin. He collaborated with Joseph *Erlanger in investigating the electrical properties of nerve fibers. Utilizing a cathode-ray oscilloscope and a sensitive amplification system they recorded the electrical impulses passing over isolated nerve fibers. The measurements of the potential cycles of different nerve fibers revealed three distinct patterns indicating that there were three major types of fibers. It was also shown that the rate of conduction varied directly with the thickness of the fiber. These studies were the foundation of the modern knowledge of action currents in nerves and were of great importance toward an understanding of the complexities of nerve impulse transmission. As a result of this work Gasser and Erlanger shared the 1944 Nobel Prize for medicine.. Working with Erlanger and others, Gasser also contributed much to the understanding of the differences between sensory and motor nerves. He also dealt with problems involving the perception of pain and the contraction of muscle as well as the coagulation of blood.

bibliography:

L.G. Stevenson, Nobel Prize Winners in Medicine and Physiology, 1901–1950 (1935), 223–8; Biographical Memoirs of Fellows of the Royal Society, 10 (1964), 75–82.

[Norman Levin]