PRATT, FREDERICK HAVEN

(b.. Worcester, Massachusetts, 19 July 1873; d. Wellesley Hills, Massachusetts, 11 July 1958)

physiology.

During a long teaching career, Pratt’s main researches were in heart and muscle physiology; his investigations into the phenomena of muscle fiber contraction are classics of their time.

The son of Frederick Sumner Pratt, a merchant descended from early Massachusetts settlers, and Sarah McKean Hilliard, Pratt entered Harvard after attending preparatory school in his native Worcester, receiving the A.B. in 1896 and the A.M. in 1898. In the latter year he reported on experiments he had been conducting for some time to determine the role of the veins of Thebesius and of the coronary veins in the nutrition of the heart, a problem to which he returned years later.

His training enabled Pratt to combine a keen interest in the theoretical aspects of physiological research, which he examined in relation to their historical antecedents, with an expertise in the use of apparatus in experimentation. After studying at the University of Göttingen and a stay at the Worcester Polytechnic Institute, he became assistant in physiology at Harvard in 1901. He graduated from Harvard Medical School in 1906. He taught physiology in Wellesley College’s department of hygiene until 1912, when he was appointed professor of physiology at the University of Buffalo. In that year he married Margery Wilerd Davis; they had five children.

The first of Pratt’s researches into skeletal muscle fiber contraction applying the “all-or-none“principle was published while he was head of the department of physiology in the medical school at Buffalo. From 1919 to 1920 he was an honorary fellow in biology at Clark University, and the next year he served as teaching fellow in physiology at Harvard. Named professor of physiology at Boston University in 1921, he remained there until he retired emeritus in 1942. Later he headed a firm supplying apparatus for physiological research. A member of the American Physiological Society and other scientific societies, he was interested in the work of the Marine Biological Laboratory at Woods Hole, Massachusetts, and the Bermuda Biology Station. He wrote several biographical studies and was especially intrigued by the biological concepts of Emanuel Swedenborg, finding them in many ways modern and in some respects anticipatory of certain of his own regarding cardiac nutrition.

The gradation of muscle activity had engaged investigators before Pratt, with his undergraduate assistant John P. Eisenberger, set out to devise a method of determining by direct observation the response of single muscle fibers to stimuli. After Henry Pickering Bowditch in 1871, studying cardiac muscle, had set forth the “all-or-none” principle, others had explored the further applicability of the rule that independent of its strength, a stimulus, if it elicited a response, evoked one that was maximal. Francis Gotch had studied nerve fibers; Keith Lucas had maintained that the contraction of individual skeletal muscle fibers in response to stimuli was an all-or-none phenomenon. In 1917 Pratt published his description of a method of stimulating a single muscle fiber, or a few at most. He utilized a capillary pore electrode having a pore of 8µ, smaller in diameter than the contractile element (a single muscle fiber of the sartorius of the frog), but noted that still smaller pores had been made. The technique provided for direct microscopic observation and for photomicrographic tracings. Also in 1917 Pratt reported studies in which the movements of a mercury globule lying on the surface of a muscle preparation were recorded, and he followed fatigue and staircase gradients as well as graded responses.

Pratt saw the problem of muscle contraction as essentially one of energy transformations and of the changes involved between stimulus and response. He demonstrated discontinuities in muscle fiber response that were interpreted as direct confirmation of the all-or-none effect; thus the graded response of skeletal muscle was explained as a summation of maximal individual fiber contractions. He drew an analogy with quantum hypotheses in describing the all-or-none response in muscle fibers.

Pratt’s researches in muscle physiology, which he carried further at Boston University, were a stimulus to other researchers. The results of investigators who later found gradation in muscle fiber response to minute excitation too small to be propagated throughout the fiber led to continuing efforts to define conducting and contractile mechanisms, as well as the recognition that certain conditions were the normal and others quite unusual.

Pratt’s experiments mark an era in the history of muscle physiology; his special interest lay in the use of apparatus, often of his own design, to study mechanical responses in muscle. He pursued research on salientian lymph hearts and on problems of nervemuscle and cardiac physiology, and developed electrical recording and timing devices. As an educator he was interested in making medical history accessible to the student of medicine.

BIBLIOGRAPHY

I. Original Works. The early papers on all-or-none response are “The Excitation of Microscopic Areas: A Non-Polarizable Capillary Electrode,“in American Journal of Physiology, 43 (1917), 159-168; “The All-or-None Principle in Graded Response of Skeletal Muscle,” ibid., 44 (1917), 517-542; and “The Quantal Phenomena in Muscle: Methods, With Further Evidence of the All-or-None Principle for the Skeletal Fiber,” ibid., 49 (1919), 1-54, written with John P. Eisenberger. Later, when physiological investigations had demonstrated certain localized graded responses within skeletal fibers, he wrote “Localized Response of the Muscle Fiber to Excitation Traversing a Quiescent Area,” ibid., 122 (1938), 27-33, with S. E. Steiman. His articles also included “Scientific Apparatus and Laboratory Methods,” in Science, 72 (1930), 431-433; and “Homolateral Synchronism of Lymphatic Hearts,” in Proceedings of the Society for Experimental Biology and Medicine, 29 (1932), 1019-1022, written with Marion A. Reid.

Some correspondence is in the John F. Fulton Papers at the Yale Medical Library.

II. Secondary Literature. The significance of Pratt’s work is discussed in John F. Fulton, Muscular Contraction and the Control of Reflex Movement (Baltimore, 1926), 48-52, 127-128; and in John F. Fulton, ed., Selected Readings in the History of Physiology (Springfield, III.-Baltimore, 1930), 221–222, and 2nd cd., compiled by Fulton and completed by Leonard G. Wilson (Springfield, III., 1966), 237-238.

Biographical sources include National Cyclopaedia of American Biography, XLVI (New York, 1963), 556; and Jaques Cattell, ed., American Men of Science, 9th ed., II (Lancaster, Pa.-New York, 1955), 897.

Gloria Robinson