History of Science-1.
Nicolaus Copernicus.
Thomas Digges.
Andreas Vesalius.
Gabriele Fallopio.
Fabricius.
Harvey.
The Renaissance was the time when western Europeans lost their awe of the ancients.
They realised that they had much to contribute to civilisation,
as the Greeks and Romans had contributed.
There was a very long period, from the time of Greeks and the Romans,
during which there was very little progress in science.
The time between 400 AD to 900 AD is called the dark ages.
The time between 900 AD to 1400 AD is called the middle ages.
For almost 1000 years, people relied on what the ancients discovered and proposed.
Science was almost at a standstill.
Structures such as the pantheon, and the colosseum were held in awe.
It appeared that these were built by a different species or gods.
They seem to think that the ancients were far superior intellectually.
People accepted the teachings of ancients philosophers like Aristotle and Euclid.
This was the way things were at the beginning of the Renaissance.
The Romans contributed relatively very little to the scientific view of the world.
This means that knowledge of the nature of universe, has been essentially unchanged for 1500 years.
Once the ideas were challenged, progress was very rapid.
After 15 centuries of stagnation, there was rapid progress in science, in the next 5 centuries,
from the time of Copernicus till now.
A typical Italian in the 10th century, would have felt pretty much at home in the 15th century.
A 15 century Italian will be totally lost in the 21st century.
Such is the pace in which change has been taking place in the last 5 centuries.
Copernicus was an intermediate figure in the scientific revolution.
In one important way he resembled the ancient greek philosophers, rather than the modern scientists.
He did not carry out experiments.
He did not do any significant observations of the heavens.
He did not expect any one else to try to test his ideas.
His idea was only an ‘idea’, what we now call as a ‘thought experiment’.
Ptolemy, during the greek times, had proposed a complicated system of how the universe works.
Copernicus came up with a new and simpler idea, to explain the universe.
Unlike a modern scientist, it did not occur to Copernicus to test his idea.
Copernicus thought his model was better than Ptolemy’s model, because it was more elegant.
Elegance is a reliable guide, to the usefulness of a model.
But it is not an infallible guide.
In this case however, it turned out that Copernicus’s intuition was right.
The Ptolemaic system lacked elegance.
Ptolemy lived in the 2nd century AD.
He was a Greek who was brought up in Alexandria in Egypt.
Egypt was then under the cultural influence of Greece.
One of the works he left for posterity was a summary of astronomy.
This was based on 500 years of Greek astronomical and cosmological thinking.
The book is known by its Arabic title Almagest.
It means ‘the greatest’.
This gives some idea on how it was regarded for many centuries to come.
The book did not contain Ptolemy’s own idea.
It was a compilation of the ideas of ancient’s Greeks.
Ptolemy did some observations of the movement of planets.
He also compiled some important star maps.
The basis of the Ptolemaic system of the notion that, heavenly objects must move in perfect circles.
This was simply because circles were perfect.
This is a good example, how elegance of the model, need not necessarily be true.
At that time there were 5 known planets.
Mercury, Venus, Mars, Saturn and Jupiter.
There was also the sun, the moon and the stars.
The basic notion was that the Earth was at the centre of the universe.
The motion of a planet was described by saying that it revolved in a perfect little circle,
around a point which itself revolved in a perfect big circle around the Earth.
This is something like a ‘wheel within a wheel’.
It was called an epicycle.
Ptolemy also proposed, that there was a large crystal sphere.
This invisible sphere carried the heavenly bodies around in circles.
They didn’t actually revolve around the Earth.
They revolved around the set of points offset from the Earth.
They were called equant points.
The Earth was regarded as the central object of the universe.
Everything else revolved around the equant points.
This model was able to explain the way the Sun, the Moon, and the planets,
move against the relatively fixed stars.
The stars were considered fixed because they had the same pattern, while moving around the Earth.
The stars were thought to be attached to a crystal sphere.
The model was complicated, and some thinkers were not satisfied with that.
There were some ancient greek philosophers like Aristarchus in 3 BC,
who thought that the Sun might be at the centre of the universe, and Earth revolved around it.
This idea proposed occasionally did not find much favour.
They thought that this idea is against ‘common sense’ .
Solid Earth surely cannot be moving.
This is a good example, of why science should not rely on common sense alone.
We should spare a thought to thinkers like Aristarchus, who got it right.
In spite of this, the vast majority of people, have never heard of Aristarchus.
There were some problems with Ptolemy’s model.
One such problem is specially interesting.
According to his model the Moon must be closer to Earth at some times of the month.
This means that its size has to noticeably change.
This obviously did not happen.
This among other problems made Copernicus uneasy about the ptolemaic model.
Copernicus was born in Poland in February 1473.
His father was a wealthy merchant, and died early.
Copernicus was bought up by his uncle Lucas.
Lucas was a bishop.
Copernicus started his studies in 1491, in the university of Krakow.
This was one year before Columbus set off on his first voyage to the America’s.
In the university he became seriously interested in astronomy.
In 1496 he moved to Italy, where he studied law and medicine.
He also studied the classics and mathematics at Bologna and Padua.
He received his doctorate in Canon law from the university of Ferrara in 1503.
Copernicus was strongly influenced by the humanist movement in Italy.
By the time he completed his doctorate, he was appointed by his uncle Lucas,
as canon in a Polish cathedral.
The post was a sinecure which he held for the rest of his life.
In 1506, he returned to Poland and worked as his uncle’s physician and secretary,
until Lucas died in 1512.
After this he paid some attention to his duties as a canon, practised medicine,
and held various minor civil offices.
He still had plenty of time to maintain his interest in astronomy.
Copernicus was strongly influenced by book published in 1496.
The book was written by a German called Mueller.
Mueller developed on the ideas of his teacher Georg.
Georg was influenced by other people before him.
Mueller set out to produce a modern abridgement of Ptolemy’s Almagest.
The latest version available was a Latin translation made in the 12th century.
This itself was translated from an Arabic text.
The Arabic text was translated from the ancient Greek texts.
Georg’s dream was to update the work, going back to the earliest available Greek texts.
After the fall of Constantinople, some of the ancient greek texts was available in Italy.
Unfortunately he died before he could complete the job.
On his death bed Georg made Mueller promise, that he would complete the work.
Mueller produced his book, the Epitome.
This not only summarised the contents of the Almagest,
but added details of later observations of the heavens.
He revised some of the calculations of Ptolemy, and included some critical commentary.
The inclusion of critical commentary, was an early sign of a renaissance thinker,
that he could be an equal to the ancients.
The commentary drew attention to the fact that the size of the moon does not change,
as the Ptolemaic system requires.
The Epitome was published in 1496, 20 years after he died.
This is the book that set the young Copernicus thinking.
It is interesting to speculate that if the book had been published 20 years earlier,
that somebody else would have picked up the thread, as Copernicus was only 3 years old in 1476.
Copernicus formulated his own model of the universe, by 1510.
He circulated a manuscript called, Little commentary, to a few close friends.
There is no evidence that he was concerned about the risk of persecution by the church.
In fact the little commentary found a place in a lecture in the Vatican,
which was attended by Pope Clement VII.
One of the cardinals who attended the lecture urged him to publish the works.
Copernicus eventually published his ideas in 1543.
He called it, ‘On the revolution of the celestial spheres’.
We might wonder why the delay.
One is Copernicus was busy, as a canon and as a doctor.
As a mathematician he worked on the plan for the reform of the currency.
He also put in good use, his training in law.
He also briefly as a solider in Teutonic Knights.
There was a second reason for his reluctance to publish.
His model did answer old puzzles, but raised many new questions.
Copernicus did not do much observations.
He was a thinker and a philosopher, more like the ancient greeks.
He wanted a model in which everything moved around the single centre,
at an unvarying rate.
He wanted this for aesthetic reasons.
Putting the Sun, at the centre of the universe was a big step.
But, we still had the Moon orbiting the Earth.
Epicycles were needed to explain this, and why the planets seem to slow down,
or speed up in their orbits.
Somehow Copernicus did not like epicycles.
The biggest problem with the Copernican model, was the stars.
If the Earth was orbiting around the Sun, and the Stars were fixed to a crystal sphere,
outside the sphere carrying the most distant planet,
then the Earth should cause an apparent motion in the stars themselves.
If you sit in a moving car, you seem to see the world outside moving past you.
If you sit in a moving Earth, why don’t you see the stars move.
The only explanation seems to be that the stars must be very much further away from the planets.
Then why would God leave such a large empty space?
This was very puzzling.
If the Earth moves, why isn’t there a constant gale of wind blowing past?
Why doesn’t the Earth’s motion cause the oceans to slop about, producing great tidal waves?
Why doesn’t the motion shake the Earth?
In the 16th century motion meant riding on a galloping horse,
or in a carriage pulled over rutted roads.
The concept of smooth motion was difficult to grasp at that time.
There was another problem.
If the Sun was at the centre of the Universe, why didn’t everything fall into it.
All Copernicus could explain was, that ‘Earthy’ things tend to fall to Earth,
and solar things tend to fall into the Sun and so on.
What he really meant was, ‘we don’t know’.
This gives us some idea, of the kind of problems that thinkers like Copernicus had to face,
when formulating revolutionary ideas of a Sun centred Universe.
It also teaches us that a scientific model doesn’t have to explain everything to be a good model.
Rheticus was a professor of mathematics in the university of Wittenberg.
He realised the importance of Copernicus’s model, and persuaded Copernicus to publish it.
At last Copernicus agreed to publish his great book, perhaps because he was now an old man.
Rheticus delegated the publishing task to Osiander, who was a Lutheran minister.
As a Lutheran, Osiander had reason to fear that the book might not be well received.
Martin Luther was a contemporary of Copernicus.
He lived from 1483 to 1546.
Luther had objected to the Copernican model.
He thundered that the Bible says that the Earth is the centre.
Without consulting Copernicus, Osiander wrote a preface to the book,
that the model was not intended as a description, of the way the universe is.
He said, it’s only a mathematical device to simplify calculations of the movement of the planets.
Copernicus had no chance to complain about the preface, because he died in 1543,
the same year that the book was published.
There is an unverified tale that he received a copy of his book, on his death bed.
The irony is that Osiander’s view is quite similar to modern scientific world view.
All our ideas about the way the universe works, are now accepted as simply models put forward,
to explain observations, and the result of experiments, as best as we can.
If we are planning a rocket flight to the moon,
a model with Earth as the centre of the universe is good enough.
If we are planning a flight to Saturn, this model will not work.
We need a better model, like the sun centric model to plan this flight.
NASA scientists treat the sun as the centre of the universe, for these flights,
even though they know very well, that the Sun is in orbit, around the centre of Galaxy, the milky way.
By and large, scientists use the simplest model they can, which is consistent with all the facts,
relevant to a particular set of circumstances.
They do not use the same model all the time.
The publication of Copernicus’s work called ‘De Revolutionibus’ was accepted,
without a murmur by the catholic church.
The book was largely ignored by most people.
The original edition of 400 copies could not be sold.
The book was condemned by the European protestant movement.
However in England, the book was well received by the cognoscenti.
This was at the time Henry VIII married his last wife, Catherine,
in the same year that the book was published.
What was impressive about the Copernican model, that by putting the Sun at the centre,
the orbits of the planets fell into a logical sequence.
Since ancient times, it had been a puzzle that Mercury and Venus could be seen,
only around dawn and dusk.
The other 3 planets could be seen at any time in the night.
Ptolemy explained this by saying that Mercury and Venus kept company with the Sun.
In the Copernicus model Mercury and Venus were closer to Sun compared to Earth,
and their orbit was inside the orbit of the Earth.
Mars, Jupiter and Saturn had orbits outside the orbit of the Earth.
Copernicus could work out the time it took for each planet to orbit around the Sun.
These periods found a neat sequence from Mercury through Venus, Earth, Mars to Jupiter and Saturn.
Mercury had the shortest year, while Saturn had the longest year.
He also could know the relative distances of the planets from the Earth.
One of the few people who saw the implication of the Copernican model,
was the English astronomer, Thomas Digges.
Thomas Digges like his father, Leonard Digges popularised science.
Leonard Digges was born in 1520.
He was educated at Oxford.
He became well known as a mathematician and a surveyor.
He wrote several books in English.
This was unusual at that time, when scientific books were written in Latin.
His first book was published in 1553.
Because it was in English, it became a best seller.
The book had a perpetual calendar, astronomical material, and weather information.
It was something like a farmer’s almanac.
Leonard Digges career came to an abrupt end in 1554.
Queen Mary came to the throne in 1553, on the death of her father Henry VIII.
He took part in an unsuccessful rebellion led by protestant Thomas, against catholic queen Mary.
He was condemned to death, which was later commuted.
He forfeited all his estates.
When Leonard died in 1559, his son Thomas was 13 years old.
He was looked after by his guardian John Dee.
Dee was a typical renaissance natural philosopher.
He was a good mathematician, student of alchemy, and an astrologer to queen Elizabeth 1,
who came to the throne in 1558.
He had a library of more than 1000 manuscripts and books, including the works of Copernicus.
Thomas Digges devoured these books.
Thomas also studied the heavens.
He made an observation of a supernova in 1572, which was later used by Tycho Brahe.
The most important publication of Thomas was in 1576.
It included a detailed discussion of the Copernicus model.
He went one step further and said The Universe is infinite.
He drew a diagram with the Sun at the centre, and planets in orbit around it.
He indicated a multitude of stars extending to infinity in all directions.
This was an astonishing leap into the unknown.
Leonard had invented a telescope during his life.
It is highly likely that Thomas was looking at the milky way through a telescope.
He was convinced that the multitude of stars that he saw,
were other Suns spread through out the Universe.
Thomas did not devote his life to science, and did not follow up his ideas.
He became a member of parliament, and an advisor to the Government.
He died in 1595.
By that time Galileo was an established professor of mathematics in Padua.
The catholic church was turning against the Copernican model.
This was because it had been taken up by Bruno, who was a heretic.
Bruno was involved in a long trial, which would end in him being burnt at the stakes, in 1600.
Bruno was not burnt because he supported the Copernican model,
but because he was a heretic, and was burnt for his religious beliefs.
He was a follower of a movement called Hermetism.
This cult based its beliefs on the teachings of the Egyptian God Thoth.
Hermes was the greek equivalent of Thoth, hence Hermetism.
The Sun was a God to the Egyptians.
Catholics like Philip II of Spain subscribed to Hermetism beliefs.
Even John Dee was a believer.
Bruno took an extreme view that the Egyptian religion was the true faith.
He propounded that the catholic church should find a way to return to this old faith.
He was arrested and was condemned on charges of Arianism,
and for indulging in occult magical practices.
Bruno was not a martyr for science, he was a martyr for magic.
It was incidental that he supported a sun centric model, based on the ancient Egyptian world view.
After 1600 the Copernican model was frowned upon by the church.
Moving with its customary slowness, it took the church till 1616,
to place De Revolutionibus on the index of banned books.
(They took it off the index in 1835).
The work of Copernicus, was built on the rediscovery,
of the work of the ancient greek astronomer, Ptlomey.
Vesalius of Brussels was another renaissance thinker.
His work was built on the rediscovery,
of the ancient greek physician, Galen.
These ancient works were known to Byzantine civilisation, Arabic civilisation,
and the civilisation during the dark ages in western Europe.
The fall of Constantinople led to the spread of the ancient documents and translations,
westwards into Italy and beyond.
There was a humanist movement in Italy during the renaissance.
This helps stir the beginnings of the scientific revolution.
At that time it was not viewed as a revolution.
Copernicus and Vesalius, thought they were building on ancient knowledge,
rather than starting anew.
The process was more evolutionary than revolutionary.
The real revolution was the change in mentality.
The renaissance thinkers regarded themselves as equal to the ancients.
It is only with the work of Galileo, and later Newton, that the process of investigation of the world,
became revolutionary, to the ways of modern science.
Galen was a greek physician born in 130 AD, in the part of Asia minor, that is now Turkey.
He lived till the end of the second century.
He was the son of a wealthy architect and farmer.
He received the finest of education.
His education was steered towards medicine, after his father had a dream,
foretelling his success in the field.
He studied medicine at various centres of learning, including Corinth and Alexandria .
He was the chief physician for gladiators at Pergamum, for five years from AD 157.
He then moved to Rome, where he became the personal physician and friend,
of the emperor Marcus.
He also served Commodus who was the son of Marcus.
Commodus became the emperor in AD 180.
These were turbulent times for Rome.
There was constant warfare on the borders of the empire.
The empire was divided into the eastern and western parts in AD 286.
Constantinople was founded in AD 330.
Galen was a prolific writer.
Like Ptolemy he summed up the teaching of earlier thinkers,
notably Hippocrates.
The modern idea of Hippocrates being the father of medicine, was a result of Galen’s writing.
He had somewhat of an unpleasant personality.
Galen’s claim to fame, was for his skill in dissection, and the books he wrote,
about the structure of the human body.
Surprisingly dissection was frowned upon during those times, though they had frequent wars.
Galen’s work was carried out on dogs, pigs and monkeys.
He did manage to dissect a few human bodies.
His conclusions about the human body, based on studies of other animals,
were incorrect in many ways.
Nobody seems to have done any serious research for another 1300 years.
Galen’s work was regarded as the last word, in human anatomy, till the 16th century.
The revival of Galen was part of the humanist obsession with all things Greek.
Catholics and protestants believed that the teachings of God were corrupted,
by centuries of interpretation and amendments to biblical writings.
They started studying the earliest Greek version of the bible, rather than the translations into Latin.
As part of this trend Galen’s works were published in the original Greek in 1525.
Ironically medical men could not read Greek.
They studied the Latin translations of the 1525 Greek edition.
Thanks to the translations and the printing press, Galen’s work was widely disseminated.
This was the time that Vesalius was completing his medical education.
He was born in Brussels in 1514.
His father was the royal pharmacist to the holy roman emperor Charles 5.
In 1533 he enrolled to study medicine in Paris.
Paris was at the centre of the revival of Galenism.
He also learnt his skill at dissection.
His Paris studies came to an abrupt end in 1536, when there was a war,
between France and the holy Roman empire.
(Historians point out that the holy Roman empire, was neither holy, nor Roman, nor an empire.)
He returned to Louvain, where he graduated in medicine in 1537.
He was so interested in dissection, that he once stole a body, for his study.
He then went to the university of Padua where he got his degree of doctor of medicine.
He was appointed to the faculty at Padua.
He was popular and successful teacher, in the Galenic tradition.
Unlike Galen he was an able and enthusiastic dissector of human beings.
The authorities in Padua supplied him with the bodies of executed criminals.
Sometimes they delayed the execution, to fit in with Vesalius’s schedule, and need for fresh bodies.
It is during this time, he realised that Galen had very little experience in human dissection.
This encouraged him to prepare his own book, on human anatomy.
In the middle ages dissections if at all done, was done by surgeons, who were considered inferior.
The professor would lecture on the subject from a safe distance.
Vesalius performed his dissections himself, and explained to his students,
the significance of what was been uncovered.
He also employed superb artists to prepare large diagrams, used in his teachings.
Six of his drawings was published in 1538.
Three of his drawings was by Stephen, a highly respected student of Titian.
Stephen was probably the main illustrator for the master work published in 1543, called Fabrica.
Fabrica had an accurate description of the human body.
It emphasised the need for a professor to do his own dissection.
It stressed the importance of accepting the evidence seen,
rather than behaving implicitly the words handed down by the ancients.
It was realised that the ancients were not infallible.
It took a long time for the study of human anatomy to become respectable.
The proper study of the human body started with the work of Vesalius,
and the publication of the Fabrica.
The Fabrica was a book for experts in medicine.
He wanted to reach a wider audiences.
He produced a summary for students, called the Epitome, which was also published in 1543.
After laying the ground work for a scientific approach to the study of anatomy,
Vesalius suddenly abandoned his academic career before he was 30 years old.
It is not clear whether Vesalius was tired of the criticism of his works,
or whether he wanted to practice medicine rather than teach it.
In any case, armed with copies of his two books,
Vesalius approached Charles 5.
He was appointed as a court physician, which was a prestigious post.
The disadvantage was that there was no provision for the physician to resign,
during the lifetime of the emperor.
However, Charles 5 allowed him to leave his service in 1556, with a pension.
This was shortly before he abdicated.
Vesalius took up a similar post with Philip II of Spain, who was the son of Charles 5.
As a foreigner there was some hostility towards Vesalius.
Vesalius went on a pilgrimage to Jerusalem.
While returning by ship, he became ill and died in 1564.
He was 50 years old then.
Apart from his works, Vesalius had a profound influence,
through his successors in Padua.
Notable among them was Harvey.
Harvey discovered what turned out to be one of the greatest insights of the 17th century.
He discovered the circulation of blood.
Another special contribution of Harvey was that he proved that the discovery was real.
The direct line from Vesalius to Harvey involved only 2 other people.
Gabriele Fallopio was a student of Vesalius.
He became the professor of anatomy in Pisa.
He came back to Padua in 1551.
He died in 1562 at the age of 39.
He made his mark on human biology in 2 ways.
He discovered the Fallopian tubes, which still bears his name.
Fallopio described the links between the uterus and the ovaries, as flaring out at the end,
like a brass trumpet, or tuba.
This somehow got mistranslated as tube.
Modern medicine is struck with this inaccurate description.
His greatest contribution to anatomy was the role as teacher of Fabricius.
Fabricius succeeded Fallopio, as professor of anatomy in Padua.
Fabricius was born in 1537.
He graduated from Padua in 1559.
He was appointed as professor of anatomy in Padua, in 1565.
A lot of Fabricius work concerned embryology, and the development of the foetus.
This he studied in hen’s eggs.
His most important contribution was the first accurate and detailed description,
of the valves in the veins.
He published his book in 1603.
He did not know the purpose of the valves.
He thought they were there to slow down the flow of blood from the liver,
to allow it to be absorbed by the tissues of the body.
Fabricius retired in 1613, and died in 1619.
Harvey studied under Fabricius in Padua from 1590 to 1602.
From Galen’s time the belief was that blood was manufactured in the liver,
and carried by the veins throughout the body, to provide nourishment to the tissues.
It was thought that in this process blood was used up, a new blood was constantly manufactured.
The arterial system was seen as carrying ‘vital spirit’ from the lungs and spreading it to the body.
Incidentally oxygen was not discovered till 1774.
Servetus was born in 1511.
He wrote that blood travels from the left side to the right side of the heart, via the lungs.
Galen thought and taught that this happens via tiny holes in the dividing wall of the heart.
Servetus reached his conclusions on theological grounds, not on dissection.
His theological views was anti trinitarian.
He did not believe that Jesus Christ was God incarnate.
He suffered the same fate as Bruno, but at different hands.
Calvin was at the height of his reforming activity, at that time.
Servetus repeatedly wrote to him about his ideas.
When the book was published, Calvin contacted the authorities in Vienna,
and had the heretic imprisoned.
He was later burnt at the stake by Calvinists in 1553.
His books were also burnt.
Servetus had no influence on science of that time.
But his story gives us an insight of the world in the 16th century.
Since Galen’s time, it was thought that veins and arteries carried two kinds of blood.
One of Harvey’s key discoveries was that the valves in the veins,
described by his teacher Fabricius, was one way systems.
It allowed blood to flow only towards the heart.
Harvey was born in 1578, eldest of seven sons of a farmer.
He was educated in Cambridge, and got his B.A. degree in 1597.
He moved to Padua where he was taught by Fabricius.
He graduated as a doctor of medicine in 1602.
Galileo was also teaching at Padua at that time.
It is unlikely that they met.
Harvey returned to England in 1602 and married Elizabeth.
Elizabeth was the daughter of Browne, he was the physician to queen Elizabeth 1.
Moving in royal circles, Harvey had a distinguished medical career.
He was elected as a fellow of the college of physicians in 1607.
In 1618 he became one of the physicians to king James 1, who succeeded Elizabeth 1, in 1603.
In 1630 Harvey was appointed as personal physician to king James’s son, Charles 1,
who came to the throne in 1625.
He was appointed as a warden in Oxford in 1645 when he was 67 years old.
Civil war was raging in England at that time.
Oxford came under the influence of parliamentary forces in 1646.
Harvey retired from Oxford.
He was technically the royal physician to Charles 1, till Charles was beheaded in 1649.
In 1654 he was elected as the president of the college of physicians.
He declined this post due to age and ill health.
He died in 1657.
The great work for which Harvey is remembered,
was actually carried out in his spare time.
This is one reason it took him till 1628 to publish his results.
The book was called, ‘On the motion of the heart and blood in animals’.
Another reason was, that even 50 years after the publication of Fabrica,
there was still strong opposition to revise Galen’s teaching.
Harvey had to present an open and shut case, in order to establish the reality of blood circulation.
The way he presented the case, makes him a key figure in the history of science.
He pointed the way forward for scientists in all disciplines.
Earlier philosophers would dream up abstract hypothesis, about the workings of the natural world.
Their thinking were based on principles of perfection, rather than observation and experience.
Harvey actually measured the capacity of the heart.
He worked out how much blood it was pumping into the arteries each minute.
He calculated that the heart pumped out 60cc of blood every beat.
This works out to about 260 litres in an hour.
This would be 3 times the weight of an average person.
The body could not be manufacturing so much blood.
A lot less should be continuously circulating in the arteries and veins.
He used a combination of experiments and observations to prove his case.
He pointed out that poisons spread rapidly due to blood circulation.
He also observed that the arteries near the heart are thicker, then those further away.
This would be required to withstand the greater pressure near the heart.
Harvey did not have a perfect scientific thinking.
He believed that spirts kept the body alive.
It is a common misconception that Harvey, was the first person to describe the heart as only a pump.
It was Descartes, who actually took that step.
Descartes published his ‘Discourse on method’ in 1637.
He described the heart as purely mechanical pump.
Harvey’s work was still a profound step forward.
He emphasised the importance of knowledge derived from observation and experience.
Harvey’s ideas were not universally accepted at first.
The microscope was developed in 1650.
This discovered the tiny connections between arteries and veins.
This closed the gap in Harvey’s findings.
The microscope is a powerful example of the connection between progress in science,
and progress in technology.
We cannot say that proper science began after Harvey.
The person who best fits the description of the first scientist, was already at work,
before Harvey completed his work.
The person who deserves this title was Galileo.