by Hp Newquist
Galen’s research explored so much of the body that doctors and medical scientists used his ideas for more than a thousand years. That created a problem because very few people tried to improve on his studies and learn more about blood in the centuries after Galen’s death. Thus, doctors practiced medicine using all the right ideas Galen had alongside the wrong ones, such as the two different kinds of blood.
It would be another thousand years before someone figured out that blood was the most important fluid in the body, and that the heart, lungs, and all the other organs needed blood to survive.
CHAPTER 3
Making Progress
Egypt was one of the most advanced civilizations, if not the most advanced, of the ancient world. Even as far back as 3100 B.C., Egypt’s accomplishments were the envy of other nations. From designing pyramids and allowing medical experiments to building libraries and making mummies, the Egyptians demonstrated that they were technologically and intellectually far ahead of most of the world.
This was especially true when it came to learning about the human body. Egyptians had allowed Herophilus to come from Greece and open up the cadavers of nonroyal citizens in order to learn about anatomy. Egypt eventually produced its own scientists and doctors, whose skill rivaled those in Europe. It was an Egyptian doctor who figured out how blood flowed inside humans.
Ala al-Din Abu al-Hassan Ali ibn Abi-Hazm al-Qurashi al-Dimashqi, known simply as Ibn al-Nafis, lived in the thirteenth century in Cairo. He was born in Syria and went to Egypt—like others before him—to practice medicine. He became a great physician and wrote numerous books about medicine. Unlike Hippocrates or Galen, he realized that blood traveled inside a single network, the circulatory system. Ibn al-Nafis found that the heart was the central organ in this system and that it was the pump that kept blood moving throughout the body.
His most important discovery was that blood flowed from the heart to the lungs and back again. This was the first time that anyone had confirmed there was a direct connection between the dark blood from the veins and the bright blood from the arteries. It was all the same blood, but it changed as it passed through the heart and lungs and was exposed to air.
When not studying human anatomy, Ibn al-Nafis wrote books—lots of them. He wrote eighty books on medicine alone, but he also wrote about the Islamic religion, law, philosophy, proper diet, and even a novel known as The Kamiliyah Treatise, a work that many consider the world’s first science fiction novel.
Unfortunately, the Egyptian empire and its accomplishments all but disappeared after it fell under Roman rule. European culture and thinking came to dominate Egypt, in part because Europeans viewed the Egyptians as idol-worshiping inferiors. Over the course of hundreds of years, less and less importance was given to study and research performed by native Egyptians. Thus, Ibn al-Nafis’s work was little known outside of Arab countries. Only centuries later did the rest of the world realize the groundbreaking nature of his work.
This was unfortunate, because it took another three hundred years for the Europeans to discover the relationship between the lungs and the heart for themselves. Even then, it remained a secret to most of Europe because of the way in which the discovery was revealed.
Europe was in turmoil during this time. The period from about the fifth century to the twelfth century was called the Dark Ages—for a very good reason. Entire countries had been destroyed by wars, diseases, and famine. Many regions of Europe had no laws or governments. Schools disappeared. The study of medicine and science all but dried up.
The Egyptians built a thriving culture based on education and experimentation before becoming isolated from the rest of the world.
To make matters worse, various forms of the plague—a disease that can infect the bloodstream and the lungs—showed up regularly during the Dark Ages. Plagues were a problem not only during this time; they continued ravaging people until modern times. During the 1300s, one instance of a plague called the Black Death killed twenty-five million people in Europe. That was about one-third of the entire European population. The plague did even more damage in Asia, where, it has been estimated, as many as fifty million people died.
Every form of the plague (there are three) is deadly. One of its symptoms is bleeding from the mouth—not a natural occurrence. As the plague spread, people avoided those who had bloody mouths.
A superstition arose that those with blood in their mouths were vampires, drinking the blood of the healthy to try to save themselves.
Since people in Europe had little or no education, they readily believed such superstitions. This period gave rise to ideas about witches and warlocks, as well as werewolves and vampires. There were no scientists—and no books or newspapers—in Europe to inform people otherwise. People would believe almost anyone who had a good explanation for what was going on around them—whether it was true or not.
Into this confusion came the strangest doctors to ever practice medicine: barbers. Yes, barbers, the people best known for cutting hair. During the Dark Ages and beyond, many barbers learned how to be surgeons. This happened because of two simple facts. The first was that many real surgeons died during plagues because they had been infected by the people they treated. The second was that barbers knew how to use razors, which was an important skill when you had to cut someone open. The lack of doctors and the ability to handle a very sharp knife gave barbers the opportunity to “play doctor” for real.
The easiest medical procedure for these barbers to perform was bloodletting, which around this time was given a serious, scientific-sounding name—phlebotomy. It became one of the most common forms of treating sickness all over Europe. Phlebotomy was thought to cure everything from colds and allergies to stomachaches and chicken pox.
In the Middle Ages, barbers performed brain surgery.
A guide to bloodletting from a sixteenth-century German textbook.
An image of a Frenchwoman undergoing bloodletting.
Even after doctors took back medicine from the barbers around the 1400s, bloodletting continued. Good doctors prided themselves on their ability to take blood well enough that they didn’t have to cut up their patients too badly. To aid them in this procedure were special tools called lancets. Lancets were like scalpels, and extremely sharp. They were developed to poke small holes in the skin, usually in the arm or leg. Doctors had to be in careful to hit a vein properly so as to open it up but not cut it in half. When the patient started bleeding, the blood was drained into a measuring cup so that the doctor could tell how much blood was being taken. Many doctors drained several pints of blood at a time, not realizing that the body needs about eight pints to function properly. Fainting from blood loss was a common side effect.
Lancets were so important to the medical profession that when one of the first medical journals was founded, in 1823, it was named The Lancet. It is still published to this day and is considered one of the most important medical publications in the world.
Other devices were created to help doctors make the proper cuts. These included spring-loaded lancets that would punch a hole in a vein with the press of a button. Another machine, called a scarificator, had a set of adjustable metal blades set into a box that would quickly cut a patient’s skin to different depths to begin the bleeding.
Finally, there were leeches. These creatures, which are found all over the world, live on human blood (we’ll see why in a later chapter). In cases where a doctor decided that a patient wasn’t suitable to be “cut” or if there was a problem in a delicate place—especially around the face and head—leeches were used to suck the blood out of the patient. When the leech was full of blood, it was pulled off and another one put in its place.
Illustration of lancets for making different-size cuts to draw blood.
It all sounds like the making of a modern-day horror movie, but this was what scientists of the day considered the best medical treatment available.
The problem was that bloodletting didn’t work. Bloodlettin
g does not cure anything, and it never has. The best explanation for its popularity is that patients got weak from blood loss and would sleep for long periods to recuperate. Sleep is one of the best ways to treat common illnesses like the cold and flu because it gives the body a chance to focus all its resources on fighting the illness. When patients recovered after sleeping, passing out, or fainting, they frequently felt better. Doctors claimed this miraculous recovery was due to the bloodletting, not to much needed rest.
Doctors would not question the value of bloodletting until it killed George Washington, the first president of the United States, in 1799. But that was several hundred years into the future.
OUT OF THE DARK
As the dismal days of the Dark Ages faded, schools reopened. Governments were established. Scientists and philosophers once again took to learning as much as they could about the world around them.
Leeches were used for bloodletting.
Names such as Copernicus, da Vinci, and Galileo would become famous from the sixteenth century on. But one man did not become quite so famous, even though he was the first European to identify how blood flowed in die body. His name was Michael Servetus, and he was born in Spain in 1509. Although he was a very good scientist, his main interest was religion, especially the Protestant religions, which he didn’t like very much.
Servetus also had a strong interest in medicine and studied the works of Galen while attending school in France. He decided that Galen had been wrong about the circulatory system and humans’ having two types of blood. Servetus determined that blood changed from dark to light because of the way it moved from the heart to the lungs. Ibn al-Nafis had already figured this out three centuries earlier, but no one in Europe, including Servetus, knew it at the time.
An indication of Servetus’s greater interest in religion than in medicine was that he didn’t publish his findings on blood in a standard medical paper. Instead, he included his ideas as part of a paper he wrote that detailed what he thought was wrong with religions that had started up after the Protestant Reformation in 1517. His breakthrough on blood was literally buried deep within his religious writings.
He followed this paper with an anti-Protestant book that angered many church leaders, especially John Calvin, the head of a Protestant group in Switzerland. These leaders condemned him as a heretic, or nonbeliever, and threatened his life. Fearing for his safety, Servetus fled from France and, for some reason, went to Geneva, which happened to be where Calvin lived. When Calvin found out Servetus was in town, he had him arrested and imprisoned. Then he had Servetus burned at the stake, with the last copy of his book chained to his leg. The book, along with Servetus, was consumed by the fire.
Servetus’s writings on blood were eventually burned with him, as this image shows in the background.
Once again, knowledge of blood remained a secret because few doctors or scientists read Servetus’s paper, thinking it contained only comments about religion. The next time someone figured out how blood flowed, it would have to be from scratch.
The man who finally brought the study of blood and the circulatory system out into the open for all to see was an extraordinary British surgeon named William Harvey. He was born in 1578 and was given a scholarship to medical school at the age of sixteen. He traveled all over Europe, studying at different universities, and was exposed to a wide variety of medical beliefs and procedures.
By the time Harvey became a doctor, many governments had begun to allow some basic study of human anatomy through dissection—the cutting up of body parts to study their internal structure. Like the Egyptians many years before, government tended to restrict this study to the corpses of criminals. For example, England had very specific laws that permitted medical study only on the bodies of convicted murderers who had been executed. This meant that few bodies were available for study, and medical schools sometimes paid grave robbers to bring them fresh corpses so that surgeons could be trained before they operated on live patients. (It wasn’t until a law was passed in 1832 that medical professionals were allowed to legally use donated bodies for research and study.)
Harvey’s drawing of blood vessels showing from underneath the skin.
In 1628 Harvey wrote a book about his medical research that changed medicine forever. He had performed experiments on a number of people, many involving the veins in the arms, and also explored the insides of animals. One of his experiments was very simple: he would tie a tight bandage around a patient’s upper arm. This restricted the blood flow into the forearm, making it a little bit cooler than the rest of the body. When he untied the bandage, the vessels would swell, and he could see the veins in the forearm and the wrist bulge out. He also saw raised parts of the veins, small bumps that were little valves.
Harvey discovered that the entire circulatory system was one big network that recycled the same blood over and over. It was a circular system, and blood traveled around in a giant loop. He also realized the importance of the heart’s connection to the lungs in refreshing the blood with oxygen. This fresh blood was sent out through the arteries, and used blood was returned to the heart via the veins.
Just as important, he realized that veins contained tiny valves that allowed the blood to flow in only one direction. This was very different from the belief that blood just washed back and forth in the body like ocean waves. By showing that everything traveled in one direction, Harvey could trace the path of the blood through all the organs, including the kidneys, liver, and spleen, which were important in keeping the blood and the body clean.
Harvey’s writings were read by many scientists, and his discoveries changed medicine forever. From that point forward, doctors knew how blood traveled through the body. However, they still didn’t know what blood did. After all, Harvey had shown them where the blood went, but not what its purpose was. And it didn’t prevent doctors from continuing the popular practice of bloodletting.
In a strange twist of fate, William Harvey died at the age of seventy-nine of a stroke, a condition that is caused by too little blood flowing to the brain.
TRANSFUSING BLOOD
Once the medical community was convinced that blood traveled to all parts of the body in one direction, it decided to start putting things into blood. This was a very risky idea, but doctors thought that if the body responded to certain herbs and fluids that were eaten and ended up in the stomach, then maybe it would be good to put these in the blood. Fortunately for the patients of the day, many of these early tests were tried on animals. Everything from water to wine was inserted into the bloodstream in an effort to see what happened. Scientists quickly found out that these substances do not mix well with blood. The results were usually grim, and the subjects either got very sick or died.
A British physician named Robert Lower hit upon the idea of adding blood to the bloodstream. Perhaps the blood from a healthy individual could be added to the blood of a sick individual, and thus make the sick individual better. This process was called a blood transfusion. He tried it by experimenting with dogs, beginning in 1665. First Lower drained the blood from one dog until it was almost dead. Then, using goose quills as an injection device (syringes with needles hadn’t been invented yet), he drained the blood from a second dog into the first one. The first animal recovered with no visible problems. It was the first successful blood transfusion ever.
That experiment led others to think that maybe they could control an imbalance in the humors with different kinds of blood. What if the blood from a nice individual was put into the body of a violent one? Maybe that would make the violent individual more gentle. The blood from a beagle might calm down an angry hound. More important, they wondered, could it be done with humans?
Jean-Baptiste Denis performed blood transfusions between humans and animals.
Lower wasn’t the one to find out. A Frenchman named Jean-Baptiste Denis tried transfusion on a human patient before Lower could (which angered Lower and his British friends to no end). But Denis didn’t use huma
n blood on his patient. Like most doctors, he thought that all blood—no matter what the animal—was the same. Dogs and pigs and deer and lions and cows—all had red blood, just like humans. As far as science knew in the 1600s, it was all the same stuff. And it was easy to get blood from a farm animal. There was no reason to take blood from a healthy person and possibly make that person sick. Besides, healthy people needed to keep their own blood “humor” in balance.
In 1667, while Lower and other doctors in England were deciding how to handle the transfusion of blood into humans, a fifteen-year-old boy was brought to Denis. The boy was feverish and faint, and had become very weak. Denis decided that the best thing to do was to transfuse lambs’ blood into the boy. Surprisingly, the patient got better. Denis then performed transfusions on three men shortly thereafter, and it appeared to help them. Other doctors all over Europe started trying transfusions.
