Beginnings of Change, 1500-1700

Causes and explanations

Physiology

Whereas medieval scholars had little idea about how the human body worked, early modern scientist-physicians – armed with the tools of mathematics, chemistry, microscopes and scientific method – ripped a hole in Galen.  They did not always ‘get it right’, but they made significant steps forward – key examples are:

  •   The Swiss alchemist Paracelsus (d.1541) postulated that the body was comprised, not of four humours, but of chemicals – he thought Sulphur (combustibility), mercury (fluidity), and salt (stability).  This idea had a massive impact on physiology and inspired a school of 'iatrochemists' (who believed the body was a collection of, and influenced by, chemicals). 

  •   Circulation: In 1628 the English physician William Harvey published De Motu Cordis (On the Movement of the Heart, 1628), proving that the heart circulates blood around the body … disproving Galen’s theory that blood was made in the liver and used up by the body.  He also demonstrated that arteries do not contain air, but carry only blood.

  •   Nutrition: In 1648 Belgian physician van Helmont revised the medieval idea of nutrition (ie that food was turned into nutrition in the liver, to energy in the heart and to senses in the brain), to a more accurate theory whereby food was 'fermented' by acid in the stomach. 

  •   Respiration: In the 1660s and 1670s English scholars Robert Hooke, and then John Mayow, disproved Galen's theory that breathing was to cool the heart.  Hooke showed (by artificially inflating a dog’s lungs) that breathing was essential to life and Mayow (who hypothesised that there was some kind of gaseous 'spiritus nitroaereus' in the air – ie what we call oxygen) proved that air entered the arterial blood in the lungs. 

  •   Movement: Cambridge Professor Francis Glisson at (1650-1670s) proved that muscle motion was not (as medieval medicine taught) by the inflation of the muscles, and suggested that muscle tissue was ‘irritable’ (ie reflex response).  The Italian mathematician Giovanni Borelli disproved the idea that 'animal spirits' passed to the muscles and instead suggested “a sudden ebullition” excited by the nerves. 

  •   In 1701 the Scottish physician Archibald Pitcairne argued that bodily functions were determined by mechanical factors best explained by Newtonian physics rather than the imbalance of humours.  This led to a short lived 'iatromechanical' school of physiology.  Italian Professor Giorgio Baglivi likened the body to a machine, with shears (teeth), a flask (stomach), tubes (blood vessels) and a pump (heart).

Impact

  •   Academics:

  ◦   The Oxford Experimental Philosophy Club was discussing Harvey's ideas in the 1650s, and Oxford Professor Thomas Willis teaching Harevy's ideas in the 1660s.

  ◦   Cambridge and the Royal College of Physicians had accepted Harvey by the 1670s, and discussed iatrochemical and iatromechanical models in advanced lectures.

  ◦   The Royal Society published new findings in its Transactions.

  •   Everyday Medicine:

  ◦   The new physiological discoveries undermined Galen, but offered no proven alternatives.  They were theoretical, and offered no methods how they might be applied to pathology, diagnosis or treatment.  As a result, the new ideas had little to no impact on normal pathology or diagnosis.

Going Deeper

The following links will help you widen your knowledge:

  The significance of Paracelsus

  The significance of Sydenham

Case Study: William Harvey

Case Study: The 1665 Plague

- BBC Sounds on Paracelsus

YouTube

 Mr Cloke on Harvey, Sydenham and the Causes & Treatments of Disease

Pathology

The scholars of the Renaissance were humanists, and they rejected the idea that God controlled everything; the idea, therefore, that disease was a divine punishment or demonic possession receded – though not wholly: astrology figured largely in medicine into the 18th century, and there was a witch craze at the start of the 17th century. 

From the late 15th century, early modern pathology focussed on ‘necropsy’ – performing autopsies to try to find the evidence of disease.  The result was that knowledge of the effects of disease became clearly known, but less so the causes. 

A second focus was on classification of diseases by their nature, symptoms and signs, as pioneered by French physician Jean Fernel in the early 15th century.  The result was similar – a huge accumulation of factual knowledge, but no real advance in the understanding of the causes of disease.

Indeed some of the new ideas which replaced the medieval ones were at least as bizarre:

  •   Paracelsus rejected the idea that disease was caused by imbalnces of the humours; instead he blamed five external ‘entia’ – the stars, poison, constitution, spiritual influences and divine will – which disturbed the body's chamical balance. 

  •   Fernel talked about the poisoning of the 'vital spirits', or assigned the cause to the humours. 

  •   Italian physician Girolamo Fracastoro, On Contagion (1546) blamed ‘seeds’, maybe carried on clothes or in the air. 

  •   van Helmont blamed an imbalance in what he called the body’s ‘Blas’ (vital force). 

  •   Dutch scientist and physician Fransiscus Sylvius (d.1672) – the founder of the iatrochemical school – blamed the balance of acids in the blood (which does, admittedly, cause acidosis), abnormal juices and their ‘fermentation’. 

  •   English physician Thomas Sydenham (d.1689) – whom you will read in your textbook or Google “challenged the long-held theory of the four humours” – believed that a patient's illness was not the result of general causes, but of the specific identifiable disease itself.  He suggested that diseases could be classified as botanists had idenified an classified plants.  This is regarded as a major step forward in pathology.  Nevertheless, he still blamed ague (malaria) on the warmth of the sun acting on the humours, and treated smallpox with a ‘cooling regime’. 

  •   The new disease of syphilis was variously attributed to: on excessive heat and moisture; excess of black bile; God’s punishment for immorality; poisoned air, food, or semen; the planetary conjunctions of 1484 or 1485; cosmic corruption of the air and earth; a plague brought back from America; contagion; and (finally!) … physical transmission by sexual intercourse. 

  •   The new sweating sickness (the ‘English sweat’ – probably a form of influenza) was blamed on a miasma, humoral imbalance, contagion, divine wrath, or ‘softness’. 

As we saw in physiology, the advances in pathology undermined medieval explanations, but they were theoretical and offered no alternatives. 

Therefore, when Marcello Malpighi (one of the greatest physiologists of the time) died of a stroke in 1694, and his autopsy was performed by Giogio Baglivi (another of the greatest physiologists of the time) … Baglivi, who found congealed blood and an ounce of ‘yellow phlegm’ in the brain, declared that the necropsy:

“proved that the glands in the body had thrown an acid fluid into the mass of blood, and that the glands of the liver had thrown it into a melancholy humour, and that these two sorts of humour being carried into the vessels of the brain had disposed the blood to coagulate there”. 

It shows what one historian has described as “the almost unbreakable hold of ancient humoral pathology” on early modern pathology. 

Source C

Doctor's Visit by Jacob Toorenvliet (c.1666).  The patient, weak, fully-clothed, is comforted by the maid.  The elderly doctor feels her pulse (a sign of pregnancy) while examining a flask containing her urine (another indicator).  On the table lie a pen, a blank piece of paper (perhaps for a prescription?) and a sliced lemon (to counter any bad air).  The pot might contain salves or aromatic balms for application after diagnosis.  It portrays a thoughtful consultation involving pulse,, uroscopy, and aftercare. 

Source E

A realy useful checklist of advances and stagnation in Thorne & Stark, Medicine through time (2016).  Click on the picture for a larger image. 

Diagnosis

Two approaches, both popular in 17th century England, might be seen as advances on medieval diagnosis:

  •   Paracelsus stressed the need for direct observation and personal experience in understanding diseases, rather than just relying on ancient texts; the doctor should identify the specific organ affected and the 'poison' responsible.  He devised a 'points score' system to identify one disease (pyoderma gangrenosum, a skin condition causing ulcers) ...  yet he also believed that diagnosis needed spiritual insight (revealed through faith and the Holy Spirit). 

  •   Sydenham encouraged doctors to move away from their reliance on medicl texts, and instead to base their diagnoses on close observation of the symptoms; this was a return to the 'clinical observation' of Greek medicine, and earned Sydenham the title: 'the English Hippocrates'. 

However, given the theoretical, elite nature of early modern advances in physiology and pathology, diagnosis for the majority of doctors remained basically unchanged since medieval times.  So – although they would be aware of Vesalius and Harvey, and the works of Paracelsus and van Helmont were popular in England – for their everyday practice doctors still relied on Hippocrates and Galen, along with Sydenham's Observationes Medicae and Processus Integri.   

Doctors continued to examine urine flasks, observe patients’ appearance and behaviour, and feel the pulse, and were still guided by humoral assumptions as they came to their diagnosis.  And they would still carry a Vademecum as a quick checklist.

Although most physicians had abandoned astrology by 1700, doctors still saw medicine as an ‘art’ – a skill not a science ...  and more so, not less, given the influence of Paracelsus.   Even things as basic as the pulse watch and thermometers were rare in diagnosis until the 18th century.

Determining factors:

Communication – the printing press had clearly made the new ideas available across Europe – the Royal Society's Transactions were aimed specifically at scientists –  there was an international academic network sharing ideas.  Moreover, this was not only for physicians and scholars, but to ordinary people such as John Donne, allowing (eg) the works of Paracelsus and van Helmont were popular in England. 

Science and learning – learning was advanced by scientific method and experiment (eg Harvey's identification of the curculation of the blood/ Hooke’s experiments with dogs’ lungs).   Newtonian physics led to iatromechanical theories.  The discovery of chemicals led to an iatrochemical school of medical thought.

Attitudes: Faith – Humanism led doctors to downgrade astrology/spiritual explanations and seek natural causes EXCEPT Paracelsus's ideas were derived from alchemy and emphasised the inspiration of the Holy Spirit. 

Attitudes: Authority – despite repeated proofs that Galen and the Four Humours were wrong, notice that there was still a lengthy gap between discovery and dissemination: even universities took 40+ years to intoduce Harvey's ideas, and doctors were still using Galenic methods well into the 18th century. 

Attitudes: Patriarchy – notice how ALL the scholars and physicians highlight above were male; by the 17th century, medicine in England had become almost exclusively the preserve of men. 

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