Haller Establishes Physiology as a Science

Date 1757-1766

Between 1757 and 1766, Haller published his textbook Elementa physiologiae corporis humani, a comprehensive work that established physiology as a science independent of anatomy. Haller’s discovery that contractility is a quality inherent in muscles, while sensitivity and pain perception characterize nerve function, laid the foundation of modern neurology.

Locale Lausanne and Bern, Switzerland

Key Figures

• Albrecht von Haller (1708-1777), Swiss physician, anatomist, botanist, bibliographer, and poet
• Herman Boerhaave (1668-1738), Dutch physician and professor of physiology, botany, and chemistry
• Luigi Galvani (1737-1798), Italian physician
• Alessandro Volta (1745-1827), Italian physicist

Summary of Event

The development of human physiology as a science required accurate anatomical understanding of the human body. Anatomical knowledge was gained through dissection of cadavers, a practice that began in Europe in the fourteenth century and gradually gained recognition in the fifteenth and especially the sixteenth century. Scientific developments of the seventeenth century led scientists to regard humans as machines, and this mechanical approach dominated research at that time. Albrecht von Haller, a former student of the Dutch mechanist Herman Boerhaave, coined the term anatomia animata, or living anatomy.

Boerhaave viewed the human being as a machine composed of hollow and solid elements. Influenced by the teachings of Boerhaave, Haller furthered physiologic understanding by carrying out numerous animal experiments. His areas of interest were multiple: He studied the development of chicken embryos and adopted the preformationist standpoint that the ovum contains a miniature being—a homunculus (little human)—that starts to grow once activated by semen. His work in the field of pulmonology demonstrated that lung expansion requires an airless pleural space. His research correctly ascribed digestive properties to saliva and pancreatic juices, and his understanding of the process of hearing approached that of modern science.

In his study of muscle and nerve action, Haller designed hundreds of animal experiments. Denuded anatomical areas were exposed to thermal, chemical, or mechanical injury. The different reactions of the animal to the noxious stimuli allowed Haller to differentiate between“irritable” and “sensible” tissues. Muscles exhibited “irritability,” a contraction of muscle fibers upon stimulation, whereas nerves displayed “sensibility” and were responsible for pain perception. The term “irritability” had been used a century earlier by British physician Francis Glisson, who presumed that all tissues had the ability to contract. Haller, however, showed through judicious experimentation that irritablity was restricted to muscle fibers.

Having observed that compression not only of the spinal cord but also of specific brain areas interfered with the transmission of nerve impulses, Haller could only speculate on the mode of communication between nerve and muscle. He discarded the possibilities of electrical conduction and vibration, hypothesizing that “juice” flowing from the central nervous system through the peripheral nerves led to muscle contraction. The concepts of irritability and sensibility, which Haller first announced in 1739, were discussed again in his monograph De partibus corporis humani sensibilibus et irritabilibus (1753; A Dissertation on the Sensible and Irritable Parts of Animals, 1755). The full development of Haller’s concept of nerve and muscle function was published in Elementa physiologiae corporis humani (1757-1766; elements of human physiology).

During his lifetime, Haller published three textbooks of physiology, including a heavily annotated edition of professor Boerhaave’s lectures, a text entitled Primae lineae physiologiae (1747; Dr. Albert Haller’s Physiology, 1754), and the multivolume set Elementa physiologiae corporis humani, in which he systematically presents the complete anatomic and physiologic knowledge pertaining to the human body. Elementa physiologiae corporis humani not only contained macro- and microanatomical information on organ systems but also encompassed their physical and chemical properties. Each organ structure and the experiments leading to the understanding of specific organ functions were discussed in minute detail. References were provided for the theories and experiments cited, and credit was given to scientists who had contributed to the data.

Haller critically analyzed the available information and avoided drawing unfounded conclusions. In addition to offering critical analysis of the existing body of knowledge about human physiology, he discussed those contexts in which insufficient or inconclusive data were available to draw firm or meaningful conclusions. His text therefore stood as a complete, well-researched scientific work of experimental physiology, detailing the entire state of the field as it then existed and emphasizing what now is the golden rule of medical science: Knowledge and understanding of the human body must be based on valid, well-conceived experiments and reflect the efforts of each contributing researcher.

Haller, who had conducted the majority of his experimental work during the seventeen years he taught as professor of anatomy, botany, and surgery at the University of Göttingen, began writing Elementa physiologiae corporis humani upon his return to Switzerland in 1753. The first volume, Fibra, vasa, circuitus sanguinus (fibers, vessels, the circulation of blood) was published in 1757, and he completed the work in 1766, when the eighth volume, Fetus hominisque vita (the human fetus and the life of man), came out in print. Like the first volume, the second volume, Sanguis, ejus motus, humorum separatio (1760; blood, its motion, and the separation of fluids), was dedicated to Frederick V of Denmark.

In the preface to volume 5, Sensus externi interni (1763; external and internal senses), Haller defended his theory of irritability and sensibility. The third volume (1761) treated respiratory function and voice, and volume 4, which appeared in 1762, discussed the brain, nerves, and muscles. Volume 6, Deglutitio, ventriculus, omenta, lien, pancreas, hepar (swallowing, stomach, omenta, spleen, pancreas, liver), and volume 7, Intestina, chylus, urina, semen, muliebra (intestine, chyle, urine, seminal fluid, female organs), were published in 1764 and 1765, respectively.

A complete German translation of Haller’s monumental work appeared between 1759 and 1776. Portions of the work have also been translated into French and Dutch, but very little into English. In 1774, the first eight pages of Fibra, vasa, circuitus sanguinus were translated into English and published in The Medical Magazine: Or, General Repository of Practical Physic and Surgery under the title Elements of Physiology. Further translations were published in subsequent numbers.

Haller’s support of preformationism may have delayed progress in the understanding of embryology, but his breakthrough work in neurology spurred scientists to explore how transmission of nervous impulses occurred. Luigi Galvani and Alessandro Volta, drawing inspiration from Haller, later demonstrated that muscles would contract when electrically stimulated and so paved the way for the development of electrophysiology.

Significance

Albrecht von Haller’s contributions to modern physiology facilitated the understanding of pathologic processes and ultimately led to progress in the treatment and prevention of disease. A mechanistic understanding of life evolved from the simplistic view of bodies as compositions of “beams and levers” and “pipes and vessels” to Haller’s realization that living tissues are characterized by their specific functions: The intrinsic property of muscle is to contract and that of nerves is to feel.

The discovery that the reaction to a stimulus depended on the tissue’s organizational makeup—that is, the discovery that tissue was specialized, or programmed to act a certain way—was entirely new. Haller’s perception that tissues possess “vital properties” stimulated scientific thinking, leading to the concepts of an “internal milieu” and “body homeostasis.” In the nineteenth century, it led to the further discovery that even nerves themselves were specialized, as the same stimulus applied to different nerves could produce sight, smell, touch, taste, or sound.

It became increasingly apparent that the harmonious functioning of living organisms required an intricate messenger system: The role of the binding of hormones to their receptors in initiating the informational cascade between different organs has been elucidated, as well as the role three-dimensional protein structures play in cellular functioning.

Bibliography

Hall, Thomas. Ideas of Life and Matters. Vol. 1. Chicago: University of Chicago Press, 1969. Discusses the Hallerian concepts of irritability and sensibility.

Piccolino, Marco. “Biological Machines: From Mills to Molecules.” Nature Reviews: Molecular Cell Biology 1 (2000): 149-153. Concerns the evolution of mechanistic thinking.

Porter, Roy. Blood and Guts: A Short History of Medicine. New York: W. W. Norton, 2002. Discusses dissection of human cadavers.

‗‗‗‗‗‗‗. The Greatest Benefit to Mankind. New York: W. W. Norton, 1998. Information on the different modes of scientific thought during the Enlightenment.

Roe, Shirley. The Natural Philosophy of Albrecht von Haller. New York: Arno Press, 1981. Includes an English summary of Haller’s preface to the first volume of Elementa physiologiae corporis humani.

Rothschuh, Karl. History of Physiology. Huntington, N.Y.: Robert E. Krieger, 1973. Contains discussion of Haller’s thoughts on different organ functions.

Simmons, John. The Scientific One Hundred: A Ranking of the Most Influential Scientists, Past and Present. Secaucus, N.J.: Carol, 1996. A brief discussion of Haller’s scientific importance.

Steinke, Hubert, and Claudia Profos. Bibliographia Halleriana. Basel, Switzerland: Schwabe Verlag, 2004. An extensive bibliography of Haller’s works, including secondary literature.