Life Sciences in the Twentieth Century
by Garland E. Allen
Despite its great importance in the growth of the biological sciences in this century, physiology has received far less attention from historians of science than is its due. This may be in part because physiology’s close historical relationship to medicine has made it seem more the province of historians of medicine. There is also the fact that physiology underwent its revolution in methodology over a century ago, with the widespread introduction of physicochemical and experimental methods to supplement descriptive, anatomical work. Whatever the exact reason, the result is that the reader looking for an entrance into the general history of twentieth-century physiology will have to consult a variety of separat, more specialized sources.
Rather than covering the vast array of subjects that rightfully fall under the history of physiology (such as plant physiology and pathology, etc.), I focus on three areas that have been major concerns in the twentieth century: general physiology, neurobiology and endocrinology. For a brief introduction and overview of twentieth-century physiology, it is worthwhile to consult Karl E. Rothschuh’s History of Physiology (Huntington, N.Y.: Krieger, 1973). Chapter 7 (pp. 264-361) deals with the twentieth century; while it does not provide in-depth coverage, the broad outline establishes the framework within which more specialized topics can be placed.
The Prussian-born American physiologist Jacques Loeb (1859-1924), a long-time investigator at the Rockefeller Institute and a close professional friend of such figures as T. H. Morgan, Boss Harrison, J. McKeen Cattell, and W.J. V. Osterhout, set the style of experimental and quantitative biology that influenced a whole generation of biologists, especially in the United States. Loeb championed what he called “the mechanistic conception of life”–the title of a major address he gave in 1911 and of a book of essays collected in 1912 (Cambridge, Mass.: Harvard Univ. Press, 1964). The reprint edition benefits from a superb introduction by Donald Fleming. The Mechanistic Conception of Life was a celebration of the mechanistic materialist viewpoint in twentieth-century biology. The introduction and a selection of several of the essays make for stimulating reading and are well within the reach of most undergraduates, especially those with a year or more of college biology. A new biography of Loeb is Philip J. Pauly’s Controlling Life: Jacques Loeb and the Engineering Ideal in Biology (New York: Oxford Univ. Press, 1987). As the title suggests, Pauly emphasizes that Loeb’s guiding ideal was the scientific control of life.
Opposition to the “mechanistic conception of life” came from a number of sources–principally embryology and areas of general physiology–from the 1920s onward. Prominent among those who advanced a more holistic approach were the physiologist Walter Bradford Cannon (1871-1942) and the physiological chemist Lawrence J. Henderson (1878-1942). Cannon’s work, is summarized in his popular book The Wisdom of the Body (1932; New York: Norton, 1960), which is eminently accessible to undergraduate readers. Henderson’s work is summarized, along with a number of other chemical topics, in his semipopular The Fitness of the Environment (1913; Boston: Beacon Press, 1958). This paperback edition contains an introduction by George Wald. The development of the idea of homeostasis is the subject of a superb essay by Donald Fleming, “Walter B. Cannon and Homeostasis,” Social Research, 1984, 51:609-640.
Henderson’s work has been the subject of several studies. John Parascandola’s “Organismic and Holistic Concepts in the Thought of L. J. Henderson,” Journal of the Histoty of Biology, 1971, 4:63-113, relates Henderson’s scientific to his philosophical work. Henderson and Cannon were strongly interested in social regulation and equilibrium, as was fitting for products of the “Progressive Era,” and sought in physiological processes analogies for the notion of social and economic balance. A specific discussion of Henderson’s view of the interrelationship between social and physiological equilibrium theory can be found in Cynthia Eagle Russett’s The Concept of Equilibrium in American Social Thought (New Haven, Conn.: Yale Univ. Press, 1968). See also Stephen J. Cross and William R. Albury, “Walter B. Cannon, L.J. Henderson, and the Organic Analogy,” Osiris, 1987, N.S. 3:165-192.
Endocrinology (the study of the nature and effect of hormones, or “chemical messengers,” produced by the endocrine glands) is an area of general physiology that has shown enormous growth in the twentieth century. It has also been the subject of numerous historical studies. Arthur F. Hughes has prepared a brief but useful introduction titled “A History of Endocrinology,” Journal of the History of Medcine and Allied Sciences, 1977, 32(3): 292-313. While it is largely descriptive and chronological, Hughes’s study demonstrates the close link between clinical pathology and the gradual discovery of the role of hormones in maintaining physiological balance. The history of endocrinology is the subject of a special issue of the Journal of the History of Biology, 1976, 9. A general introduction to the historiography of endocrinology is provided for the volume by Diana Long Hall and Thomas F. Click (pp. 229-233). Hall has explored some social and technical aspects of the history of sex-hormone research in “Biology, Sex Hormones, and Sexism in the 1920s,” Philosophical Forum 1974, 5:81-96. In this fascinating article she suggests that sexist biases about the importance of male over female hormones proved to be a barrier to the technical solution of problems associated with extracting, isolating, and characterizing the chemical nature of sex hormones (principally testosterone and estrogen) in the 1920s. On a somewhat more specific aspect of endocrinology, Michael Bliss’s The Discovery of Insulin (Chicago: Univ. Chicago Press, 1982) provides a close picture of the technical problems that investigators in any field of endocrinology had to surmount in order to identify, isolate, and purify a given hormone. The insulin story also provides a fascinating picture of the role of drug companies in encouraging and financing hormone research in the period (1920s) before government subsidy of basic scientific research.
Although neurobiology (as it is now called) has always been subsumed under physiology, its rapid growth in the twentieth century, along with its institutionalization in separate university departments and separate funding programs, has made it an almost completely autonomous discipline. Neurobiology can be divided into two major areas: neurophysiology, or the study of the process by which nerve cells transmit a message; and neurology, the study of the structure and organization of the nervous system. One of the few comprehensive historical reviews of both areas is Mary A. B. Brazier’s “The Historical Development of Neurophysiology,” in Handbook of Physiology, edited by J. Field, H. W. Magoon, and V.E. Hall (Baltimore:Waverly, 1960), Section I, Volume I, pp. 1-57. Although this article lacks historical analysis, it does trace the history of a variety of neurophysiological problems from ancient times to the early decades of this century. Another general work, though less systematically organized than Brazier’s, is The Neurosciences: Paths of Discovery, edited by Frederic G. Worden, Judith P. Swazey, and George Adelman (Cambridge, Mass.: MIT Press, 1975). Two articles in this collection stand out as particularly interesting: Richard Jung’s “Some European Neuroscientists: A Personal Tribute” (pp. 477-511), and Judith P. Swazey and Frederic G. Worden’s “On the Nature of Research in Neuroscience” (pp. 569-587). Swazey and Worden look at the development of twentieth-century neurobiology in terms of Thomas Kuhn’s concept of scientific revolution.
Two major questions confronted neurologists at the end of the nineteenth and beginning of the twentieth centuries: What was the basic anatomical element of the nervous system (individual cells, or a continuous nerve network)? How were parts of the nervous system (e.g., peripheral nerves and spinal cord) integrated to produce an overall functioning system? The first question involved considerable debate in the period of the 1870s through the 1890s, though it was resolved ultimately in favor of the neuron theory (individual nerve cells as the basic structural and functional unit of the nervous system) by the early 19009. Central to that debate was the work of the Spanish cytologist Santiago Ramón y Cajal (1852-1934), whose autobiography Recollections of My Life, translated by E. Horne Craigie with the assistance ofJuan Cano (Philadelphia: American Philosophical Society, 1937), contains considerable information about the debate, the clash of paradigms, and Ramón y Cajal’s exquisite techniques for bringing about the resolution. A more recent and historically oriented account is Susan Billings’s “Concepts of Nerve Fiber Development 1839- 1930,” Journal of the History of Biology, 1971, 4:275-306, which shows how study of the embryological development of the nervous system (which Ramón y Cajal wisely exploited) helped to demonstrate that the nervous system arises from many discrete individual cells.
The structural and functional organization of the nervous system has been an area of great advancement during the twentieth century. Much work on the mode of action of the reflex response (as well as on how reflexes are learned) and on the relation between inhibition and excitation of nerve tracks was done by Russian neurologists in the latter part of the nineteenth and especially the early part of the twentieth century. The chief figures there were Ivan Michailovich Sechenov (1829-1905) and Ivan P. Pavlov (1849-1936). Pavlov’s inerest in digestion led him, under Sechenov’s innuence, to study the now-classic conditioned reflex involved in salivation. Pavlov’s life and work is the subject of one English-language volume: B.P. Babkin’s Pavlov, A Biography (Chicago: Univ. Chicago Press, 1949). This source provides valuable insight into a whole school of neurological work that has had as much influence on psychology as on neurobiology in this century.
While the general features and functions of the reflex were understood by the turn of the century, its manner of organization (especially in terms of connections with the brain) was not. A towering figure in elucidating the relationship between central and peripheral nervous systems, and especially the integrative function of the spinal cord, was the British physiologist Charles Scott Sherrington (1857-1952). Regnar Granit’s biography, Charles Scott Sherrington, An Appraisal (London: Nelson, 1967), is outstanding, though it suffers somewhat from historical presentism since the author is himself a distinguished neurobiologist. That deficiency is not a problem in Judith Swayze’s Reflexes and Motor Integration: Sharington’s Concept of Integrative Action (Cambridge, Mass.: Harvard Univ. Press, 1969). Swayze concentrates on a detailed but clear and insightful analysis of Sherrington’s scientific background, his experimental methods, and the development of his hypotheses about integrative action.
The history of neurophysiology is less extensively explored than that of neurology, partly because major progress has been made only in the past several decades. What few historical sources exist treat specific problems and are thus episodic. Concerning the development of the neurotransmitter hypothesis (that conduction across the synapse between adjacent neurons occurs by a chemical rather than electrical process), its antagonists and protagonists, see Michael V. L. Bennett’s “Nicked by Occam’s Razor: Unitarianism in the Investigation of Synaptic Transmission,” Biological Bulletin, Suppl., June 1985, 168:159-167. This article is the only source I know of that deals with this intriguing controversy in mid-twentieth- century neurophysiology.
- Forward and Introduction
- General Sources
- Experimental Embryology
- Heredity (Genetics)
- Evolutionary Theory
- Biochemistry and Molecular Biology
- Ecology and Human Behavior
- Biology and Society