Francis Glisson

Francis Glisson (1599–1677) was an English physician, anatomist, and natural philosopher who held the Regius Professorship of Physic at Cambridge for four decades. He is best known in the history of science for two things: his role in establishing Harvey’s circulation theory at Cambridge and the College of Physicians, and his concept of irritabilitas — the idea that living tissue possesses an intrinsic power to perceive stimuli and respond to them. Glisson’s theory of irritability was not a simple laboratory finding. It was embedded in a systematic natural philosophy that held matter to be self-mobile, endowed with perception and desire at the level of the fibre. This put him at odds with both Galenic humoralism and Cartesian mechanism. When Haller refined and redeployed the irritability concept a century later, he acknowledged that Glisson had been there first — though with a broader and philosophically loaded version of the idea that Haller’s more precise, experimentally derived account deliberately narrowed.

Career and Institutional Position

Glisson was a product of Caius College, Cambridge, where he took his MD in 1634. He was a Fellow of the College of Physicians and delivered anatomical lectures there. From 1636 he served as Regius Professor of Physic at Cambridge, a chair he held until his death — an institutional tenure that gave him the position to shape how the next generation of English physicians understood Harvey’s new anatomy.(French, 1994)

That role was not merely ceremonial. French’s account of Glisson at Cambridge shows him actively disseminating Harvey through lectures, disputations, and academic orations, and speaking in Harvey’s favor at the College of Physicians from 1639 onward, including as Goulstonian Lecturer.(French, 1994) The first known formal defence of the circulation at Cambridge was William Wallis’s thesis of 1641, defended under Glisson’s supervision.(French, 1994) When Jean Riolan, the Parisian anatomist, published his Opuscula in 1649 arguing for a “mutilated” circulation that preserved most of Galenic anatomy, Glisson organized a disputation targeting Riolan’s two specific modifications — that blood passed through major anastomoses rather than the substance of the parts, and through septal pores rather than through the lungs.(French, 1994) Glisson’s diagnosis of Riolan’s motive was precise: Riolan accepted the anatomical force of Harvey’s demonstrations but could not accept the destruction of humoral medicine that a full circulation would entail.(French, 1994)

Natural Philosophy: Self-Mobile Matter

Glisson’s approach to anatomy and physiology was built on a distinctive natural philosophy that French, his modern historian, identifies as its principal characteristic: the doctrine that matter is self-mobile, or “energetic” in Glisson’s term. This followed from Glisson’s theological starting-point. Nature, for Glisson, was not God — he maintained the scholastic distinction between natura naturans (God) and natura naturata (creation).(French, 1994) Strictly speaking, “nature” referred to the essence of corporeal bodies, over which God ruled as law-giver.(French, 1994) But the mode of that law-giving mattered enormously: Glisson believed matter was, like spirit, ultimately a divine emanation, and therefore had its own innate mobility rather than requiring externally imposed motion.(French, 1994) His theological framework was also shaped by Protestant varieties of belief at the deepest level. French identifies a third category of knowledge of God that Glisson added to the medieval distinction between scripture and the book of nature: a personal knowledge of God, described as “different in those who expect to be saved and those who do not.”(French, 1994) This put him in direct opposition to Descartes, for whom all motion was derived from outside and imposed on passive matter.

Glisson could not accept that the heart alone caused circulation, because Harvey’s account of forceful systole appeared to him to treat the blood as passive matter pushed by an external force.(French, 1994) His alternative was that both the arteries and the blood actively participated.(French, 1994) This position required an elevation of the blood’s status: Glisson argued, through his student Thomas Barwell in 1653, that the blood was “the highest and principal part of the body” — “original life” itself — a thesis that conflicted with received philosophy, in which blood was merely a “similar” (homogeneous, structureless) part ranked low in the hierarchy of organs.(French, 1994)

The concept of tentio was Glisson’s attempt to analyze cardiac and arterial motion in terms that avoided the connotations of traditional systole/diastole vocabulary.(French, 1994) He defined tension as the effort of pulling (conatus trahendi) against resistance, causing rigidity.(French, 1994) Mication was a second mechanism: an alternating ebullition and collapse of the blood itself, caused by the constant struggle between the innately mobile vital spirits of the blood and the blood’s coarser component.(French, 1994) When challenged that a heart removed from a living animal continues to beat in the absence of blood, Glisson’s response was that mication occurs in the substance of the ventricular walls as well as in the blood, and that the eventual cessation results from the exhaustion of vital spirits.(French, 1994)

Glisson attacked Descartes’ account of the heartbeat on three points: Descartes had attributed heat to the walls of the heart, whereas for Glisson the blood itself was warm and mobile; Descartes confused ordinary physical heat with innate heat; and Descartes’ inflation theory could not explain why a separated eel heart, bloodless and divided, continued to beat.(French, 1994) The critiques were pointed and engaged with Descartes’ specific text, not mere assertion.

Irritability

Glisson’s most consequential contribution to subsequent physiology was his concept of irritabilitas, first developed at length in Anatomia hepatis (1654) and extended in Tractatus de natura substantiae energetica (1672). The account in Anatomia hepatis established an equivalence among the Latin verbs irritare, incitare, exstimulare, and vigorare — all pointing to the same underlying capacity: the ability of animal fibres to be stimulated and to respond.[cang-ir88-ch02-007]

Broussais credited Glisson explicitly with the first proper theory of irritation: “he ascribes to each animal fibre, a property which he terms irritability, and of which the results are perception and desire.”(Broussais, 1831) [GAP: Explanation that Glisson’s irritability was not simply contractility and that the concept was philosophically rich and extravagant, along with Broussais’s year and motive, are unsupported by the cited card.]

Coulter’s account, in Divided Legacy, places Glisson’s introduction of the term in a specific polemical context: the word “irritability” was deployed to hypostatize the vital force into a material property — to reduce Van Helmont’s Archeus (the purposive vital force directing each organ) to something immanent in matter itself rather than a separate governing principle.(Coulter, 1975) The parallel with what Haller later did against Stahl is explicit in Coulter’s analysis: Haller used “irritability” to do to Stahl’s Anima what Glisson had done to Van Helmont’s Archeus — to locate vitality in the fibre rather than in an autonomous directing soul.

Pagel’s study of Van Helmont finds a close conceptual kinship across all three thinkers — Van Helmont, Harvey, and Glisson — in their shared insistence on form immanent in matter and individual units endowed with “natural perception.”(Pagel, Walter, 1982) The connections were real, even if Glisson’s Protestant theology, Cambridge Aristotelianism, and experimental anatomy produced a different idiom from Van Helmont’s Flemish iatrochemistry.

Relation to Haller

The relationship between Glisson and Haller is one of partial derivation and significant redefinition. Sigerist, in Great Doctors (1933), put it precisely: Haller had been “forestalled” by Glisson in the formulation of the concept of irritability, but where Glisson meant by it the general tendency of the animal body to react to environmental influences, Haller’s definition was more precise — irritability for Haller was the specific property of muscular fibres to contract in response to stimuli.(Henry E. Sigerist, 1933) Porter, in The Greatest Benefit to Mankind, describes Haller’s contribution as being made “rather in line with Glisson’s hypothesis” — the phrase acknowledging dependence while locating the decisive innovation in Haller’s experimental delimitation of the concept.(Porter, 1997)

Broussais, surveying the lineage from his 1831 polemical vantage point, characterizes the transition exactly: Haller “first determined by precise experiments, what tissues were really irritable: the result with him was, that their property was confined to the muscular fibre.”(Broussais, 1831)

Canguilhem, in Ideology and Rationality in the History of the Life Sciences, follows the concept across a longer arc: from Glisson through Haller and Bichat, the concept of irritability remained ambiguous and contested, differently bounded by each thinker who deployed it. Brown, writing at the end of the eighteenth century, effectively reverted to Glisson’s broad equivalences — irritare, incitare, exstimulare, vigorare — probably without realizing he was doing so, inheriting through his own simplifying moves a version of the concept that Haller and Bichat had worked hard to narrow.[cang-ir88-ch02-007]

Clinical Work

Before his natural philosophy consumed his later career, Glisson’s most practically significant work was his monograph on rickets — De rachitide (1651), published with colleagues including Assell and Regemorter. The rickets monograph was a collaborative clinical investigation into a disease that had become newly prominent in England, and it established Glisson’s reputation as an observer. Sigerist includes it among the generation of disease monographs that Sydenham’s method inspired: studies of apoplexy, pulmonary consumption, and occupational diseases that focused attention on particular disorders rather than general theories of disease.(Henry E. Sigerist, 1933)

Anatomia hepatis (1654) was the major anatomical treatise, in which Glisson not only described the fibrous capsule of the liver that still bears his name (“Glisson’s capsule”) but developed the irritability concept at length. The later Tractatus de natura substantiae energetica (1672) was the most purely philosophical of his major works, extending the self-mobile matter doctrine into a full account of the energetic substance underlying natural processes — a text that remains difficult and has received less historiographic attention than the anatomical works.

Natural Necessity and the Problem of Faculties

One of the tensions running through Glisson’s physiology concerned how to explain bodily action without attributing rationality, perception in the full cognitive sense, or autonomous agency to organs. His solution was the concept of “natural necessity” (necessitas naturae): natural actions are governed by necessity rather than judgment or prudence.(French, 1994) The organs do not deliberate; they act because their structure and the mication of their vital spirits compel them to act in specific ways. This allowed Glisson to eliminate faculties in the traditional scholastic sense — the pulsific faculty, the attractive faculty — and substitute events linked necessarily to structure and action. As French explains, in Glisson’s student Robert Brady’s defense of the doctrine, the pulsific “faculty” of the heart became an aptitude based on the organic constitution of the heart plus the mication of blood — not an independent entity, but a description of what happened given the relevant structures.(French, 1994)

Vital spirits were retained as the instrument of the soul, the chief element of the blood, and the single cause of both respiration and pulsation.(French, 1994) This was not simply conservative; it reflected the limits of what Glisson’s framework could dissolve into structural necessity. The spirits were themselves self-mobile and energetic, carrying the soul’s influence without the soul’s directing each individual contraction. The distinction was philosophically important — it allowed natural necessity to operate below the level of conscious direction while still linking the body’s activity to a spiritual source.

Reception and Legacy

Historians including Daremberg, Marion, Gley, and Temkin have examined the history of the concept of irritation and irritability from Glisson to Broussais.[cang-ir88-ch02-007] The concept of irritability from Glisson through Haller and Bichat was ambiguous and contested; Brown, by reverting to Glisson’s simple equivalence of irritare, incitare, exstimulare, and vigorare, ignored this historical complexity.[cang-ir88-ch02-007]

Human Notes

See Also

• william-harvey
• albrecht-von-haller
• jan-baptista-van-helmont
• irritability
• vitalism
• experimental-physiology
• cambridge-university-tradition

Sources

Evidence cited from: french-william-harvey-natural-1994, canguilhem-ideology-rationality-life-1988, coulter-divided-legacy-1975, sigerist-greatdoctors-1933, broussais-on-irritation-and-1831, porter-greatest-benefit-to-1997, pagel-vanhelmont-1982