Samuel Clossy’s Observations: an unrecognized contribution to the origin of anatomical pathology

Guillermo Quinonez
Ancaster, ON, Canada
Laurette Geldenhuys
Halifax, NS, Canada


Title page of Site and Causes of Disease by Giovanni
Battista Morgagni

It is often stated in the medical history literature that Anatomical Pathology was established as a modern science in 1761 when Giovanni Battista Morgagni published Site and Causes of Disease (Figure 1) in Italy.1,2 However, the development of the discipline was likely more complex, occurring somewhat concurrently in several European countries with publication of texts similar to Morgagni’s at a time when scientific communication in Europe was not as easy as it is today. This complex development is demonstrated by texts appearing about the same time as Morgagni’s, such as Samuel Clossy’s Observations On some of the Diseases Of the Parts of the Human Body: Chiefly taken from the Dissections of Morbid Bodies (Figure 2) published in Great Britain in 1763, only two years after Morgagni’s.3 The similarity between Morgagni’s and Clossy’s texts is remarkable.

Samuel Clossy (1724-1786) received a Bachelor of Medicine degree in Ireland in 1751. After graduation, he performed autopsies at the Steeven’s Hospital in Dublin and collected clinical cases at St. George’s Hospital in London.3 These experiences were the source of the material included in Observations. Following the publication of the text in 1763, he traveled to New York, arriving during the War of Independence and as a medical school was being established at King’s College. He took part in founding the school that later became the College of Physicians and Surgeons at Columbia University and lectured there in Anatomy rather than in Anatomical Pathology. In 1780 he returned to London and finally to Dublin in 1784, where he died two years later.4,5

Clossy was a humoralist who subscribed to Galen’s humoral theory and considered a secretion a humor, as found in Section V, Observation II of the Observations. He was also an empiricist. His philosophical background is evident, for instance when he discusses Locke’s influence on empiricism. This background also informs his understanding of the clinicopathologic method. In Observations, he also described the condition of medical practice in Dublin; and in Section IV, Observation VII, the societal attitudes toward post-mortem dissection.3

Observations does not cover the whole spectrum of diseases in each region of the body. It consists of fifty-three cases classified by body region and organ, including head, neck and chest, liver, intestines, kidneys, and urinary bladder; and one non-anatomical category, “dropsy.” The most prominent symptom or symptoms characterizing each case form the title of each case. Not all cases include autopsies, and most findings are limited to those body regions where symptoms and signs manifested in life. There is also an attempt to explain signs and symptoms. Previous experience in performing autopsies is deemed important when recommendations for treatment are given, as found in Section IV, Observation VII. References to available medical books are common, comprising those from the years 1663, 1703, and 1740. There is also a reference to William Hunter’s museum.3

Observations is structured according to a clinicopathologic method. Obs. II in Section II is a good example. After a short history, autopsy findings are briefly described. Dissections are limited to the regions that would explain the clinical presentation, including the pleural cavities, the pericardium, the lungs, and the pulmonary artery. A systematic discussion follows of the lung’s autopsy findings (lung induration); how the asthmatic symptoms are related to the lung findings; the causes of lung induration; other anatomical causes of clinical symptoms in neighboring organs such as spleen, pleura, and mediastinum; the effect of treatment on the lung findings; and the mechanism of production of the pericardial effusion. When explaining the clinicopathologic method, disease is understood to be “… an affection of the whole animal system wherein the functions of its several parts are disturbed, or such an affection of any part that disturbs its function …”; and symptom “… a preternatural affection resulting from a Disease, either of the whole system or any part therefore …” 3 The terminology reflects the level of development of anatomy at the time. No classifications are incorporated in the text.

Title page of Observations On some of the Diseases Of the Parts of the Human Body: Chiefly taken from the Dissections of Morbid Bodies by Samuel ClossyTitle page of Observations On some of the Diseases Of the Parts of the Human Body: Chiefly taken from the Dissections of Morbid Bodies by Samuel Clossy

Observations also defines certain fundamental concepts of disease, such as causality and pathogenesis. Cause is defined as “… whatever produces the diseases …” For example, simple anatomical localization of a lesion may explain symptoms. Weakness of the constituent fibers of an organ might explain a dilatation of the colon (Section V, Observation IV) or of the urinary bladder (Section VI, Observation I and II). Disease might also be due to mechanical irritation by an agent. Curiously, the shaking movement of persons when traveling in a stagecoach was considered to be the cause of urinary stones. The causes of kidney, ureteric, and bladder stones are discussed extensively in Section VI, including citing clinical and autopsy evidence, functional and environmental considerations, and crude gross chemical tests on urine. Pathogenic explanations are often based on the assumption that organs are made of fibers. This approach is used in Section V, Observation IV, entitled Suppression of the Contents of the Intestines, from weakness of their Fibres which consists of two similar clinical cases, one with and the other without autopsy. Explanations are usually mechanical (weakness, obstructions, irritation, etc.), based on common sense, and using reasoning by analogy. The use of physical formulas to demonstrate the velocity of blood is evidence of the empiricist background of the author. Explanations on the formation of dropsy and abscesses are particularly interesting. Dropsy, as noted in Section IV, Observation VII, is argued to result from three different causes: obstruction of the lungs, participation by the lymphatics, and depletion of blood. Abscesses are reasoned to originate from the blood because blood gives origin to pus. Some lesions observed at autopsy are also ascribed to the effects of treatment (Section IV, Observation VII). Salt is implicated in the pathogenesis of blisters and the effects of cautery.3

Observations also includes morphology. Gross descriptions are detailed. Weights of organs in pounds and ounces are considered in clinicopathologic correlation. Some size measurements are descriptive, as in “… about the size of a silver two-pence …” Sporadic use of the light microscope is included, as in Section V, Observation V.3

Clossy’s Observations was published in 1763, only two years after Morgagni’s Site and Causes of Disease. The texts are remarkably similar.1,3 Morgagni’s work is presented as letters, each corresponding to a clinical case with autopsy findings and clinicopathologic correlation. Morgagni has been credited to have invented the clinicopathologic approach. Yet this approach was most likely already well established in Europe at the time, since Clossy organizes his material in a similar manner. In both texts, cases are classified by body region, reminiscent of the division of the body introduced by Vesalius in Fabrica two centuries earlier.6 Both texts contain abundant references to current and past medical literature. Anatomical terminology is similar. But there also are differences. Site and Causes of Disease was published in five volumes and included cases both from Morgagni’s experience and from the current and past medical literature. The material is very well organized, including well-presented indexes. The grammatical style is excellent, Morgagni being a better writer than Clossy. Observations comprises only one volume and includes fewer cases, and only cases in which Clossy participated directly, either as clinician or as pathologist. While both texts discuss etio-pathogenesis, this receives more emphasis in Observations, suggesting that this was in the forefront of Clossy’s mind because of his philosophical background, unlike that of Morgagni.1,3

There is no evidence that Clossy knew of Morgagni’s work. Clossy collected his cases independently between 1752 and 1754 at a time when scientific communication was limited, and most likely was unaware that Morgagni was doing the same. Clossy received a copy of Sites and Causes of Disease years later, when it was translated, and he was already in New York.4 There is also no evidence that he knew Italian.

These observations support the hypothesis that Morgagni’s Site and Causes of Disease was not a unique medical text, and therefore challenge the notion that Anatomical Pathology as a modern science was established with this single publication.2 Site and Causes of Disease was an influential work until the nineteenth century. Observations, on the other hand, never became popular, possibly because Clossy never promoted it. However, the historical contribution of Observations is undeniable.



  1. Morgagni J B. The Seats and Causes of Diseases Investigated by Anatomy, in Five Books, Containing a Great Variety of Dissections, with Remarks. Translated from Latin by Benjamin Alexander. London, UK: A Millar, T. Cadell, Johnson, Payne; 1769.
  2. Long, E R. A History of Pathology. New York, NY: Dover; 1965.
  3. Clossy S. Observations On some of the Diseases Of the Parts of the Human Body: Chiefly taken from the Dissections of Morbid Bodies. London, UK: G. Kearsly; 1763.
  4. Samuel Clossy, M.D. (1724-1786), The Existing Works, with a Biographical Sketch by Morris H. Saffron, M.D. New York, NY: Hafner Pub. Co; 1967.
  5. Stookey B. Samuel Clossy, A.B., M.D., F.R.C.P. of Ireland: First Professor of Anatomy, King’s College (Columbia), New York. Bull Hist Med. 1964; 38: 153-167.
  6. Lind L R, Asling C W, Clendening L. The Epitome of Andreas Vesalius. New York, NY: Macmillan Co; 1944.



GUILLERMO QUINONEZ, M.D., MS, MA, FRCP, is a retired pathologist and former Professor of Pathology, School of Medicine, University of Manitoba. He is an Emeritus Member of the Canadian Association of Pathologists and currently an Independent Scholar.


LAURETTE GELDENHUYS, MBBCH, FFPATH, MMED, FRCPC, FIAC, MAEd, has served as Division Head and Service Chief of Anatomical Pathology at the QEII Health Sciences Centre since 2012. She is a Professor at Dalhousie University in Halifax, and a nephropathologist and cytopathologist with a secondary interest in Gynecological Pathology. She also has an interest in Medical Education and the Medical Humanities, including Medical History. She is founding member and incoming Vice Chair of the Canadian Association of Pathologists (CAP-ACP) Section on Humanities and International Health. She was trained in South Africa, and has master’s degrees in Anatomical Pathology and Medical Education.


Spring 2019  |  Hektorama  |  History Essays