by Hp Newquist
Thus says the LORD, “By this you shall know that I am the LORD: behold, I will strike the water that is in the Nile with the staff that is in my hand, and it will be turned to blood. The fish that are in the Nile will die, and the Nile will become foul, and the Egyptians will not be able to drink its water.
Exodus 7:17–18
A picture of the Nile River “turning to blood,” killing all the fish. (From the 1300s, artist unknown, British Library)
Scientists think that the “river of blood” identified in the Bible and in the legends of Sekhmet may have been caused by the red ash of a volcano or by the spread of algae that is red in color. The Nile also takes on a reddish color when it floods and red soil seeps into it.
Rivers running with blood are pretty horrific. Yet, this plague didn’t persuade the Egyptians to free the slaves, nor did the next eight plagues, which included frogs, lice, locusts, and darkness. But the tenth plague did change the Egyptians’ minds, and it too involved blood. For the tenth plague, God sent an angel to kill all the firstborn male children in Egypt. However, God warned the Israelites ahead of time to mark their doors with lambs’ blood. This would be a sign to the angel not to harm the children inside.
After all this blood, the Egyptians gave up and let the Israelites go.
Later in the Old Testament, the book of Leviticus states that blood is to be used only as part of sacrifices to God. It is to be sprinkled on altars, but no one is ever to drink it. Modern researchers think this might be a reference to other cultures of the time—primarily in North Africa and in Egypt—where people drank blood for medicinal purposes.
The biblical importance of blood extends into the New Testament, where Jesus Christ tells his disciples during the Last Supper that the meal is representative of his life. In Mark 14:23–24 the Bible says: “And he took the cup, and when he had given thanks, he gave it to them: and they all drank of it. And he said unto them, This is my blood of the new testament, which is shed for many.”
In John 19:34, as Christ is on the cross, a soldier stabs him in his side with a spear. According to the Bible, both blood and water flowed from the wound. This is interpreted to represent death, in the form of blood, and new life and purity, in the form of water.
BLOOD SACRIFICE
The reverence for blood appears to have extended to almost all ancient religions, cultures, and civilizations. Its mentions in the Old Testament date from two thousand years ago. The Chinese legend of P’an ku, the creature whose blood formed the Earth’s rivers, is over three thousand years old. The importance of blood in ancient Egyptian mythology dates from nearly six thousand years ago.
Over the course of thousands of years, blood took on a prominent role as an offering to gods. After all, if blood was part of death, and the gods were responsible for life and death, then these gods must like blood. Perhaps giving them blood more often would keep them happy and make them look more favorably on their worshipers.
This belief cropped up in civilizations around the world.
Almost every ancient culture created some sort of blood sacrifice as part of its rituals for its gods. The Hebrews used the blood of lambs to protect them from an avenging angel. Ancient Romans spilled the blood of cattle to purify their towns and drive away evil spirits. Warrior kings during the Shang dynasty in China offered the blood of their people to their dead ancestors in the hope of being victorious in war.
Lambs’ blood was used as protection in Old Testament stories, as depicted in this stained glass window.
Ancient paintings from Greece and pottery from Mayan civilizations—two cultures that existed on separate continents—depict ritual bloodletting, a process whereby blood was taken from an animal or a human as part of a ritual or ceremony.
In these ceremonies, the human being who was being sacrificed for his or her blood usually died, since it required that throats be cut, stomachs opened up, or heads removed. Taking blood for ceremonies was not a pretty sight. It involved quite a bit of struggling and screaming. And lots of blood.
A special knife used for cutting open sacrificial victims.
Ritual bloodletting—which is different from medical bloodletting, a procedure we’ll explore in later chapters—was practiced by civilizations such as the ancient Egyptians and Mayans. It was performed by a priest or tribal chief who took the spilling blood from the severed throat or stomach of the victim. The blood was collected in a special bowl, and then sprinkled over an altar or over members of the tribe to bless them. Some priests actually drank it.
Many of these rituals had very strict rules and could be carried out only by prominent members of the tribe—those considered worthy enough, powerful enough, or wise enough to take a life. Performing the rituals often involved the gathering of the entire tribe, who would watch the action. Like today’s religious ceremonies, these were very serious occasions, and sacred objects would be used to carry out the ritual. These included finely carved blades used only for drawing blood and bowls fashioned from the tops of skulls to collect the flowing blood.
Sometimes the human sacrifice was a person from a neighboring tribe who had been captured in battle or kidnapped for the event. These people must have been horrified at the thought of being killed in an enemy’s ritual. At other times, the sacrifice was someone from within the tribe who willingly offered him- or herself up. That person might have felt honored to be chosen by the tribe as a gift to the gods. The most important thing, as far as the tribe was concerned, was that these victims were giving their lives for the benefit of many others.
Blood rituals occurred all over the world. Mayan kings and queens, who ruled in Central America from nearly 2000 B.C. to A.D. 1500, would cut open their own veins so that their blood could be used during ceremonies. The Greek leader Alexander the Great (356–323 B.C.), ruler of Macedonia, was said to have started each day by sacrificing an animal with a knife and then praying to the gods over the animal’s blood.
Perhaps no society was as fond of spilling blood as the Aztecs. In the late 1400s in what is now Mexico, the Aztecs took blood sacrifice to a new level. They built pyramid temples that had altars on top. Sacrificial humans were taken up to the altars on eighteen festivals during the year to celebrate everything from the oldest members of the community to crop harvests.
An image from a sixteenth-century Spanish document showing the Aztecs performing a human sacrifice on a pyramid.
Once those to be sacrificed were on the altars, their hearts were cut out and their blood was allowed to flow down over the temple steps. The Aztecs were thought to have killed thousands of people in this way every year. They believed it was important to honor the gods with this blood because the gods had sacrificed much to create the universe. The Aztecs were just paying the gods back.
One of the unusual things about all this bloodletting is that very few cultures learned much about how the human body worked from all of the slicing and cutting that was done on sacrifices. In fact, it was considered immoral and illegal to cut open a body, alive or dead, unless this was done for purely religious purposes. The Aztecs, for instance, took the heart out of the chest of their sacrifice, but they immediately disposed of the body. They did not worry about all the parts that the heart was connected to. The body was sacred (even when it belonged to an unwilling victim) and was not to be touched for any purpose other than making the gods happy.
Making dead people into mummies was a way of preparing those people for the afterlife.
Only the Egyptians, who turned their rulers into mummies after death, were interested in what was going on in the human body. Their method of creating mummies relied upon extracting organs through tiny slits made in the skin. They wanted to preserve bodies for this trip to the afterlife (the Egyptian version of heaven and hell), so they didn’t open people up and look inside. People needed their bodies in the afterlife, and cutting up their flesh would have disfigured them.
Organs were removed so that bodies could be treated with herbs and oils, and then
stuffed with dry cloth. The heart, lungs, kidneys, and other organs were placed in sealed jars to preserve them separately. By removing these organs through surgical slits, the Egyptians became familiar with the placement of organs and the movement of fluids through the body.
Even doctors in Greece and Rome, where the great classical philosophers lived, did not examine bodies after death. It was considered inappropriate and disrespectful of the dead person. Because of this ban, doctors had little sense of how things worked inside the human body. Most of them thought that blood just floated under the skin like water in a jar.
THE FOUR HUMORS
The first ideas about what blood might actually do came from Hippocrates, a physician and teacher who lived in Greece from 460 to 377 B.C. Little is known of Hippocrates’ personal life, but he wrote extensively about the way doctors should treat their patients. Prior to his teachings, doctors were as likely to trust in magic as they were to give treatments that would help sick patients.
Hippocrates taught that doctors needed to do everything they could to heal a patient, and that they needed to always act with the patient’s health in mind. This included never knowingly doing harm, prescribing deadly drugs, and performing surgery that they were not trained for. So important were Hippocrates’ ideas that even today doctors take what is called the Hippocratic oath, a promise to treat their patients as best as they can.
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HIPPOCRATIC OATH
I swear by Apollo the Physician and Asclepius and Hygieia and Panaceia and all the gods, and goddesses, making them my witnesses, that I will fulfill according to my ability and judgment this oath and this covenant:
To hold him who has taught me this art as equal to my parents and to live my life in partnership with him, and if he is in need of money to give him a share of mine, and to regard his offspring as equal to my brothers in male lineage and to teach them this art—if they desire to learn it—without fee and covenant; to give a share of precepts and oral instruction and all the other learning to my sons and to the sons of him who has instructed me and to pupils who have signed the covenant and have taken the oath according to medical law, but to no one else.
I will apply dietetic measures for the benefit of the sick according to my ability and judgment; I will keep them from harm and injustice.
I will neither give a deadly drug to anybody if asked for it, nor will I make a suggestion to this effect. Similarly I will not give to a woman an abortive remedy. In purity and holiness I will guard my life and my art.
I will not use the knife, not even on sufferers from stone, but will withdraw in favor of such men as are engaged in this work.
Whatever houses I may visit, I will come for the benefit of the sick, remaining free of all intentional injustice, of all mischief and in particular of sexual relations with both female and male persons, be they free or slaves.
What I may see or hear in the course of treatment or even outside of the treatment in regard to the life of men, which on no account one must spread abroad, I will keep myself holding such things shameful to be spoken about.
If I fulfill this oath and do not violate it, may it be granted to me to enjoy life and art, being honoured with fame among all men for all time to come; if I transgress it and swear falsely, may the opposite of all this be my lot.
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Hippocrates, like many doctors before him, thought that blood was just one of four important liquids in the body. These were called the four humors and included blood, phlegm, yellow bile, and black bile. (The word “humors” doesn’t have anything to do with being funny, although it sounds that way. Once upon a time “humors” referred to liquids.) This belief in four humors tied in with the Greek view that nature was made up of four primary elements: fire, water, earth, and air. There was even a relationship between the four humors and the four elements. The essence of fire was thought to be part of yellow bile, earth was supposed to be contained in black bile, water was a component of phlegm, and all four elements—including air—were considered components of blood.
Each of the humors—or body fluids—controlled the body and kept it healthy. Too much of one fluid would cause particular kinds of sickness and disease. The body needed to keep the humors in perfect balance in order for people to be both healthy and happy.
The humors were defined like this:
Blood controlled general health and well-being. Too much blood caused fevers or ailments in the body.
Phlegm (mucus and saliva) controlled the body’s activity level. Too much phlegm, and a person became sleepy or lazy.
Black bile controlled emotions. Too much of it made a person sad, depressed, or irritable.
A drawing of Hippocrates, one of the world’s first great doctors.
Yellow bile controlled a person’s temper. Too much of it made him or her angry, excitable, or out of control.
Even though real bile is a form of stomach acid, it’s possible that the Greeks based their notions of bile on different blood forms: black bile could have been the dark form that clotted blood takes, and yellow bile could have been the light gold of blood plasma. Hippocrates might have seen these colors when blood stored in a container separated over time into its various parts (the way that salad dressing or fruit smoothies separate into different levels of liquid when they have been sitting around for a while).
Illustrations of the differences in the four humors from the seventeenth century.
When treating patients who were thought to have too much of one humor or another—depending on their symptoms—doctors such as Hippocrates tried removing some of the humors. This was done by making the patient throw up, by giving the patient a medicine that would cause diarrhea, or by draining specific amounts of blood from the body. It was not very scientific by today’s standards, but it was very popular two thousand years ago. Actually, it was popular until about two hundred years ago.
Hippocrates’ extensive study of patients led him to create a guide to adjusting the level of blood in a patient. He had a precise bloodletting procedure where he would cut into a patient’s vein and let a certain amount of blood flow out. Sometimes this was a substantial amount—almost enough to kill a person. This didn’t stop the doctors. They believed that the weakness the patient was feeling from blood loss was a sign that the bad humor level was being brought back to normal.
Bloodletting as a medical practice had been around since before Hippocrates was born, but no one is quite sure who first undertook the procedure or why. By the time Hippocrates got around to doing it, bloodletting was a common medical occurrence. Hippocrates, though, was better able than his predecessors to outline the most effective ways to perform it.
Hippocrates didn’t get to cut into patients to find out if there really was too much of one humor or another. Like other doctors in ancient times, he wasn’t allowed to because of the laws that protected the bodies of the dead. Thus, most of his writings were based on observations of how people behaved when they were sick or injured. This wasn’t a perfect way to learn about the body, but he had no choice. Yet, roughly seventy years after Hippocrates died, another Greek doctor found a way around the laws that prevented the internal examination of bodies.
GETTING INSIDE
Herophilus, a Greek doctor born in 335 B.C., was able to study the insides of humans by going to work in Alexandria, Egypt—across the Mediterranean Sea. Because there were no Egyptian laws at that time preventing the study of dead people, the rulers of Egypt allowed Herophilus to dissect dead bodies (called cadavers or corpses). These bodies were usually those of criminals, which made it somewhat easier for people to tolerate the idea of medical experiments on corpses.
In his studies, Herophilus examined the size, shape, color, hardness, softness, and function of internal organs. He also made detailed observations of how the human body’s insides fit together—what went where and what was connected to what. He found out that veins and arteries were different—arteries were thicker than veins, but they both carried
blood. His research was so extensive, and so original, that he is still known as the father of anatomy.
Herophilus was one of the only surgeons of his time allowed to see the insides of human bodies. There were other doctors who wanted to learn more about how human anatomy worked. The most creative of these was Claudius Galen of Pergamon, who lived around A.D. 150 in what is now modern-day Turkey. Even though he was a surgeon, Galen wasn’t allowed to experiment on living humans. His job was to fix bodies that were already damaged. However, he had an interesting job that gave him access to the inside of humans: he was in charge of operating on gladiators who were injured in battles. Many gladiators suffered severe injuries, and Galen was able to look at their insides while he tried to patch them up.
Gladiators engaging in combat.
When he wasn’t working on gladiators, Galen cut open pigs and apes to see if their insides were like ours. He saw, as Herophilus had, that a system of veins and arteries carried blood around the bodies of mammals. But he thought that this network moved two types of blood. One type was the bright red blood carried by the arteries. This blood was full of oxygen, although Galen didn’t know that. The other type was dark blood, almost maroon in color, and it was full of the dead cells and waste that the body needed to dispose of. Again, Galen didn’t know this. As far as he could tell, there were two different kinds of blood, one changing into the other as it passed through “invisible” parts of the heart. Like Hippocrates, Galen thought that people could be cured of their illnesses by bloodletting.
