‘It will have blood, they say; blood will have blood.’
Macbeth. William Shakespeare.
Over the last two to three thousand years our understanding and views about blood have evolved. This essay charts some of the major steps in the evolution of our thinking. It is not meant to be comprehensive but rather to demonstrate how changes in our knowledge, sometimes by scientists/physicians, at other times by events such as war occur. I will attempt to outline our massive increase in knowledge about blood and how this was utilized in terms of radical therapeutic interventions from the ‘Enlightenment’ to the present day.
Everybody has it and is curious about it. Over eons of time, opinions about the content and function of blood have been expressed by historians, writers and scientists/physicians.
Hippocrates (about 460-370 BCE), one of the fathers of Western medicine, lived on the island of Cos, off the western coast of Turkey. As Bynum writes, “He is shadowy but real”.1 It seems his works were probably written by followers but Hippocrates and his followers had a holistic approach to medicine. They believed in the four humors, blood, black bile, yellow bile and phlegm, a theory which was consolidated by Galen (129-210 CE). Disease then was thought to occur as a manifestation of the Gods’ displeasure, together with an imbalance of the four humors.
There was also a belief that blood contained certain characteristics such as bravery. Herodotus (484-425 BCE), in The Histories, wrote that the Scythians drank the blood of their slain enemies, using their skulls as drinking vessels.2 Presumably this practice was based on the assumption that blood contained the element of bravery of the slain warrior which would be transferred to the person consuming his blood. The Scythians were an ancient nomadic people originating in Siberia (900 BCE to around 200 BCE), extending their conquest from China to the northern Black Sea [3].3 They were fierce warriors and according to Herodotus: “None who attacks them can escape, and none can catch them if they desire not to be found.” Incidentally, they were also partial to alcohol, adopted from Greeks and Persians: “the Scythians drank to excess and got high. Feasting was an important part of Scythian funeral ceremonies – it was also important for social bonding between individuals and tribes… the Scythians adopted wine consumption from Greeks and Persians. They soon acquired a reputation for excessive drinking of undiluted wine.”4
The Romans also believed that blood contained medicinal qualities as Pliny the Elder says: ‘Epileptic patients are in the habit of drinking the blood, even of gladiators…and yet these persons, forsooth, consider it a most effective cure for their disease, to quaff warm, breathing blood from man himself, as they apply their mouth to the wound, to draw forth his very life.’5
However, the eating and drinking of blood or its by-products are forbidden in the Old Testament and also in the Quran. Yet, Roman Catholics and other Christian sects believe that wine is converted into the blood of Christ (transubstantiation) during the Eucharist, to be consumed by the celebrant and congregation as first described during the ‘Last Supper’. 6 One of the most widely known examples of drinking blood, because of its protein content, is the habit of the Maasai in southern Kenya and northern Tanzania. Similarly, Irish peasants drank cow’s blood in the 19th century, during the great famine.7 Even today an ‘Irish breakfast’ contains black pudding made from pig’s or cow’s blood and fat. Yet, in all these cases it is the high protein content, not some purported supernatural qualities, that takes precedent.
Blood-letting (not drinking) as a form of therapy was practiced in China (280 BCE), Ancient Greece, Arabia, India, Egypt, Mesopotamia and North America by the ‘medicine man’. Interestingly when it became obvious that blood-letting was of no therapeutic value, doctors continued to practice it for many years. Presumably, this was because they could charge a fee for each procedure.
There are many examples of blood being used as a reliquary for saints in the Catholic Church. One in Naples containing ampoules of blood is said to be that of St Gennaro. St Gennaro is a saint of the Roman Catholic and eastern Orthodox Churches. Legend has it that he was martyred by the Emperor Diocletian around 300 BCE. He is the patron saint of Naples and his blood is purported to liquify every September. Another ‘bloody’ religious story is that of Peter of Prague in 1263 AD. He, apparently, had doubts about the transubstantiation, until blood seeped from the consecrated host and flowed onto the corporal (a white linen cloth on which the consecrated host is placed during the Eucharistic mass).
Drawing of the ampoules said to hold St Gennaro’s blood, Naples, Italy. Public domain. Leipzig. 1860.
The Talmud (500-200 BCE) provides interesting insight into hemophilia, many centuries before the pathophysiology and genetic basis of the disease were understood. It describes a bleeding disorder which occurred only in males and was transmitted by ‘normal‘ females. Rabbi Judah the Patriarch thought that although circumcision was mandatory for all males, it could be waived if two brothers bled abnormally. This was an early description of hemophilia.
Another type of bleeding, albeit natural, is menstruation about which some strange views were held. The shedding of the endometrium together with the associated blood loss seems to promote an adverse reaction in many societies. In Ancient Rome, Pliny the Elder wrote that a menstruating woman who uncovered her body could scare away hailstorms, whirlwinds and lightning. If she stripped naked and walked around the field, caterpillars, worms and beetles would fall off the ears of corn. In orthodox Judaism the Jewish Torah prohibits sexual intercourse with a menstruating woman, also forbidding touching or passing things to each other during this time. Pope Dionysius of Alexandria (around 300 BCE) believed that, “Not even they themselves, being faithful and pious, would dare when in this state either to approach the Holy Table or to touch the body and blood of Christ.” Oriental Orthodox Christian women, such as those belonging to the Coptic Orthodox Church, do not attend church while they are menstruating. In Japan today, women are not allowed to enter Shinto shrines and temples during menstruation. Hopefully modern attitudes to physiology and medicine will change these strange beliefs.
The understanding of blood lay dormant for many millennia with Galen’s humoral beliefs holding sway until the ‘age of enlightenment’. Then William Harvey’s (1578-1657 AD) written description of the circulation of the blood in 1628 AD of the blood opened the floodgates of scientific research and discovery.8 Like many, if not all major discoveries, his observations were built upon the work of previous investigators, in this case Vesalius, Colombo, Ibn al-Nafis and Erasistratus of Alexandria. Harvey’s observations helped pave the way for investigation of blood transfusion while the development of the microscope, also in the 17th century, facilitated the first description of erythrocytes.
Competition between investigators existed as much in earlier centuries as it does today. Erasistratus (304-250 BCE) believed that arteries and veins are connected and that arteries contained ‘pneuma’ (animal spirit). Erasistratus had the benefit of dissecting cadavers but believed that arteries only contained blood because they acted as a vacuum, whereas Galen believed that arteries contained blood and ‘pneuma’.910 During the 17th century scientists/physicians in England and France vied with others in the field of blood transfusion. Members of the Royal Society endeavored to perfect the technique of blood transfusion in animals asking a number of questions which, once again, pointed to the belief that blood contained metaphysical properties. Richard Lower was particularly prominent and asked questions such as: if I transfused blood from a dog who had been trained to fetch a bone into a dog who had not, would I transfer that memory?11
One of his most egregious experiments was to transfuse blood from a lamb into a man in the hope that it would improve his mental state. It did not! Rivalry between the French Academy of Science and the Royal Society continued. Jean-Baptiste Denys in France also carried out many experiments, the most notorious of which, was transfusion of blood from a lamb into a man, again, to improve his mental health. This was followed by a hemolytic transfusion reaction and death. The French parliament thus deemed blood transfusion to be a criminal act and the Royal Society soon followed suit. Pope Innocent XI banned the practice. What surprises me most is that none of these scientists/physicians wondered if blood transfusion could be used to save the lives of wounded soldiers. It wasn’t until the 19th century that people began to understand that blood transfusion could be used to save lives while the discovery of the blood clotting cascade and blood groups heralded a new age.
About the author
Shaun Richard McCann received his M.B. from University College Dublin. He became a Member of The Royal College of Physicians in Ireland (MRCPI), by examination, in 1973. He was a specialist medical fellow at the University of Minnesota from 1974-76. The main focus of his research then was red cell structure and function, especially in hereditary spherocytosis. Click here to learn more.