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  They were also cautious about terminally ill patients:

  By recognising that the patient was going to die, and announcing so beforehand, he would be able to absolve himself of blame.

  Prognosis, in particular, was the way for a doctor to earn his reputation against the competition. A cure, or any effective treatment, was another matter. The resources open to the ancient Greeks were very limited, especially in combating disease.

  The Hippocratics believed that the human body was composed of the hot, cold, wet and dry, or alternatively that there were bodily humours – bile and phlegm, or black bile, yellow bile, phlegm and blood. While there was disagreement about the exact constitution of the body, one thing that they were generally agreed upon was that health was a balance of the constituents or humours, and disease an imbalance. They had no idea of bacteria or viruses, and no conception of a disease existing outside the body and invading it. Naïve though this theory of disease was, it was an entirely natural theory which served as a coherent basis for diagnosis, prognosis and treatment. We can see the optimism of the Hippocratics in the passage quoted earlier:

  Each disease has a nature and power of its own, and none is unintelligible or untreatable … whoever knows how to bring about moistness, dryness, hotness or coldness in men can cure [epilepsy] as well, if he can diagnose how to bring these together properly, and has no need of purifications and magic.

  The ancients concentrated on keeping in good health by means of exercise and diet (regimen). They also used purges, emetics, baths and blood-letting. This could be linked to their theory of disease. If there was thought to be an excess of one constituent (for example, hot), the treatment would be to reduce this excess until a balance was restored. So the Hippocratic treatise The Nature of Man tells us that:

  If you administer a medicine to a man which removes phlegm, he will vomit phlegm: if you administer one that removes bile, he will vomit bile.

  The Hippocratics also made a careful study of environmental factors. In Airs, Waters and Places they relate the occurrence of certain diseases to the prevailing weather conditions and the nature of the fresh water supply.

  Finally, the Hippocratics are famous for producing an ethical code for doctors, and for the Hippocratic oath. Their code was very philanthropic, and there was a definite disapproval of avaricious doctors. Here are two examples:

  In whatever houses I enter, I will enter to help the sick, and I will refrain from all intentional injustice and harm, especially from abusing the bodies of men and women, be they free or slaves. Whatever I see or hear in the course of my practice, or in my life outside my practice, I will never seek to divulge, but I will be silent, and leave these things unspoken.

  Do not be too unkind, but consider the wealth of your patients. At times, you will treat people for free, recalling to mind a previous benefaction for your present reputation. If there is a chance to treat a foreigner or a poor man, do so fully. Where there is love of man, there is also love of the art of medicine.

  The Hippocratic code of practice was important in ancient Greece, where healing procedures were completely unregulated. It also helped to separate doctors from non-doctors, a critical issue for the Hippocratics. Aspects of the Hippocratic code are still influential today, especially in relation to euthanasia. All of these important advances of the Hippocratics can be related to their struggle to establish themselves as doctors in the face of competition from other healers. In each case, the Hippocratics would have been able to say, we have the detailed objective case studies, the theory of disease, the code of practice, and so on. We are the real, professional doctors. Whether in the context of ancient Greece, with its limited resources for treating illnesses, they were any more effective than other forms of healer, is another question. What is certain is that the Hippocratics founded both the idea of the medical profession and the scientific study of medicine.

  Ancient medicine had its problems. There were very few effective cures for disease, no anaesthetics, and little in the way of analgesics or antiseptics. In general, the ancients were much better at dealing with trauma than disease. The treatment of trauma is a good deal more straightforward and evident, especially if one is just beginning the science of medicine. There was considerable practical experience of dealing with the treatment of battle casualties. The Hippocratics gave very detailed accounts of how to treat various types of wound to different parts of the body, and how to reduce fractures and dislocations. It was in the treatment of trauma that the ancient doctor really could make a difference. The height of this practice was probably reached by the battlefield medics of the Roman army, who in the first few centuries AD were highly organised and efficient, very skilled at treating cuts and amputations – so much so, that they proved better than any other army until the nineteenth century.

  The ancients were better at treating trauma to the extremities than to the torso. One major problem was that they had very little idea of the internal functioning of the body, and there was a social and religious taboo against the dissection of humans. Trying to work out the functioning of the organs of the human body from scratch is by no means easy, and the ancients often went seriously astray in this matter. Aristotle, for instance, believed that the heart was the central organ of sensation, while the brain was just there in order to cool the blood! Complicating things further was the fact that there was only a brief period during which both dissection and vivisection of humans was permitted. The later Roman physician Celsus (fl. 40 AD) tells us that:

  It is in the internal parts that pains and diseases come about, and they believe that no one who is ignorant of these parts can administer remedies for them. Therefore it is necessary to open the bodies of the dead and to examine the viscera and intestines. This was done in by far the best way by Herophilus and Erasistratus who opened men while they lived, men received from the king out of prison, and while these subjects still breathed, they observed parts which nature had previously concealed, their position, colour, figure, magnitude, order, hardness, softness, smoothness, what they touch, the advances and retreats of each, and whether any part is inserted in another or is received by another.

  However, this period did not last long. There were also debates about the efficacy of vivisection and dissection. Some thought vivisection cruel and unlikely to provide any benefit. Some thought dissection useless, since they adhered to the motto: ‘To heal the living one must study the living.’ There were also debates about whether anything could be learned from the vivisection and dissection of animals, though not about the morality of such practices. Vivisection and the use of animals in research was taken for granted in antiquity, and was not a matter of debate. The ancient Greeks and the Romans simply did not share – and indeed had no conception of – our twenty-first-century attitudes towards the rights of animals.

  Two key medical thinkers after Aristotle were Herophilus of Chalcedon (fl. 270 BC) who was very important in developing anatomy (the study of the structure of the body), and Erasistratus of Chios (fl. 260 BC) who was crucial to the development of physiology (the study of the function of the body). Herophilus made important discoveries about the brain and nervous system, and made the first clear distinction between arteries and veins. Erasistratus examined the organs and found each supplied with arteries, veins and nerves, which sub-divided beyond the limit of human perception.

  Galen

  The most famous doctor in antiquity, and the most influential anatomist, was Galen of Pergamum (c. 129–200 AD). Typical of the Hellenistic period, he was a great synthesiser and systematiser. He combined previous medical and anatomical knowledge with his own research to produce the most comprehensive system of medicine and anatomy in the ancient world. With additions and amendments from Arabic culture, Galen’s work lasted up until about 1550. At various times, Galen was physician to the Roman army, the gladiators and the Roman emperors. Whatever his experience of the human body in the amphitheatre, Galen faced one major problem. Access to human bodies for dissecti
on at his time was virtually impossible due to social taboos concerning the dead body. Galen said that:

  It is possible to see human bones. I have done so many times, when a grave has been broken open. Once a river, engulfing a recent hastily constructed grave, easily dissolved it, and with the power of its motion washed the dead body away completely. The flesh had rotted, but the bones were still held in the exact relations to each other.

  Galen thought that if one could get the opportunity to dissect a human body, which was not everyone’s luck, one should certainly take it. Occasionally the bodies of enemy war-dead were dissected. One should work on apes otherwise, in order to familiarise oneself, as far as possible, with the position of the internal parts of the body.

  It is tragic that such a brilliant anatomist as Galen had so little opportunity to examine the internal workings of the human body. He was an excellent observer of both the human and the animal body, and a gifted experimentalist, and was keen to emphasise the importance of first-hand experience in these matters. Galen was a highly systematic observer, dissector and vivisector of animals. He refuted the idea of Erasistratus that the arteries contain air by tying off arteries above and below the point where he cut them, showing them to be full of blood instead. The methodical nature of his studies can be seen in the following experiment, which was also rather gruesome, as it involved the vivisection of a pig. Galen was trying to find out which parts of the body were controlled by the nerves leading off the spine. To do this, he took a pig and severed the spinal column at each vertebra going upwards, observing which functions the pig lost with each incision.

  A good deal of Galen’s importance lay in producing a systematic and coherent account of medicine, anatomy and physiology. The Hippocratics had the idea of health as a balance and disease as an imbalance, but now Galen clarified this idea and formalised the humoural system of the body.

  Figure 29: Galen’s Humoural System. Associated Aristotelian elements are shown in brackets. There were believed to be four key humours to the human body: blood, black bile, yellow bile and phlegm. Health was thought of as a proper balance of these four humours. Disease occurred when there was an imbalance.

  The treatment of disease was an attempt to rebalance these humours. This might be done by diet, exercise, administering purgatives, diuretics or emetics, or by blood-letting. It is here that we see the basis for this ancient and medieval practice. Some patients were considered to be suffering from an excess of blood, thus upsetting the balance of the four humours. They might have some of the symptoms of high blood pressure – red face, protruding veins, etc. The cure was obvious: relieve the body of some blood, and restore the balance of the humours. Similar ideas related to other diseases. With a cold, one has an excess of phlegm; with an infection, an excess of yellow bile (i.e., pus); with coughing up blood, an excess of black bile. The humours had to be brought back into balance.

  Galen’s work on anatomy was both brilliant and fundamentally flawed. His acute observation and attention to detail allowed him to formulate the most extensive and systematic account of the human body in antiquity. The basic flaw in his work stemmed from the fact that he was unable to dissect a sufficient number of human bodies. As a substitute, he dissected a great number of the higher mammals, in particular Barbary apes, which he considered in many ways to be the animal most like man. Galen was aware of the dangers of supposing the higher mammals to be more like man than they actually are, but unfortunately he still fell into that trap. This was not discovered until the sixteenth century, when dissection in order to generate knowledge was taken up again. The study of anatomy stagnated after the fall of the Roman empire, and although some dissections were done, they were demonstrations to show students that Galen was right, rather than investigations in their own right. This was changed by Andreas Vesalius (1514–64), who began to dissect bodies for himself (rather than having a helper do it for him) and examine them with a more critical eye. This was part of the new Renaissance optimism that tried to outdo the achievements of antiquity. Vesalius recognised, for instance, that Galen’s description of the muscles of the human hand was good but slightly faulty. It was, in fact, a brilliant description of the hand of a Barbary ape. Vesalius dissected humans and apes to show that Galen had drawn some of his material from a study of apes. There was a considerable effort in the sixteenth century to purge anatomy of these errors, though Galen’s general scheme of anatomy and physiology remained intact.

  Ancient Thought on Blood

  The idea of the circulation of the blood was not formulated until the work of William Harvey (1578–1657) in the seventeenth century. Galen believed that there were two quite separate systems for the blood, and that the blood did not circulate around the body. Rather, it was slowly generated by the liver and then transported to various parts of the body, where it was consumed. There was a reasonable basis for this belief. Arterial and venous blood are different colours, scarlet and purple. Furthermore, the arteries are thicker than the veins, and carry a pulse. It is not evident to the naked eye that there is a link between the arteries and the veins (this can be seen only with the microscope). If scarlet arterial blood and purple venous blood were in the same system, then there was a need for a process which converted one to the other and vice versa. There was no idea of the role of oxygen and how it affects the colour of the blood, even though Galen realised that something important happened in the lungs with air and blood. In view of these facts, it was quite reasonable to believe that the two types of blood occupied two different systems of blood vessels.

  For Galen, the venous system carried the ‘nutritive’ (purple, deoxygenated) blood. The stomach produced a nutritive, milky substance called chyle which was passed to the liver, where nutritive blood was gradually generated. The venous system radiated out from the liver, the seat of nutrition. The veins carried the nutrition to the rest of the body, some (but not all) of this blood passing through the right side of the heart. The arterial system carried ‘vivified’ (scarlet, oxygenated) blood. This system originated in the lungs, which vivified the blood, and then carried this life-giving spirit to the rest of the body via the left side of the heart (see Figure 30).

  Figure 30: Galen’s conception of the venous and arterial systems.

  In both systems, blood did not return to its point of origin, but was gradually consumed by the body. As the arterial blood was consumed, it was necessary that some venous blood be transported into the arterial system and turned into vivified blood. There was believed to be a slight seepage from the right side of the heart to the left (the venous to the arterial) via the septum, in order that the arterial blood could be replenished. In fact, there is

  Galen’s account of the heart supported his views on the motion of the blood. The motion of the heart is actually extremely difficult to analyse, since it is very swift and it is by no means clear what is actually happening inside the heart. Galen believed that the active phase of the heart, when the muscles operated, was when the heart expanded in volume, so that the heart attracted blood into itself. The heart became smaller as the muscles relaxed, so that blood was not expelled from the heart with any great force. Actually, this is the wrong way around – the active phase of the heartbeat is the contraction. This was associated with another error on Galen’s part. For him, the active phase of the heart did not coincide with the pulse, and so he did not believe that the heart caused the pulse in the arteries. He believed that they pulsed of their own accord, and attracted blood into themselves. He thought that they were rather like the intestines. During vivisections, Galen had observed peristalsis, the process by which the gut moves food along itself by contractions. He believed that the gut attracted food into itself by this process. The pulse, he believed, was the way in which the arteries attracted blood into themselves. Attraction was a very important general principle of Galen’s physiology. Things were not forced around the body – organs attracted what they needed to themselves.

  Galen’s whole account of the ca
rdiovascular system supported the idea of a slow flow of the blood. The blood was produced slowly, distributed slowly and consumed slowly. He could quite easily account for rapid blood loss when someone was cut, and even arterial spurting (when arteries are cut, blood is thrown out in vigorous spurts). Blood can be under pressure, and so flow rapidly from a wound, without moving rapidly around the body, while the arteries would spurt because of the pulse they generate themselves.

  Harvey’s discovery of the circulation of the blood was important not only as the correct account of the distribution of blood around the body, but also as a significant blow against Galen’s physiology. Harvey discovered that the blood flowed rapidly around a full circuit of the body, that the active phase of the heartbeat was a contraction such that blood was expelled from it with considerable force, and that the pulse was due to the heart and not the arteries themselves. This dealt a severe blow to the principles of attraction that were so important to Galen.

  Galen had a coherent and comprehensive account of human anatomy, physiology and medicine. His views could be used as a basis for diagnosis, prognosis and treatment. He also gave a plausible account of the assimilation of food, the production of blood, the distribution of nourishment to the body, the heartbeat and pulse, and the production and distribution of heat around the body.

  Aristotle and Biology: Biology’s Beginnings

  While it was Galen’s work on the human body that was the bequest of antiquity, it was Aristotle and his followers who set the agenda in biology. There was no real study of either the animal or plant kingdoms prior to Aristotle. A standard criticism of Aristotle and other ancient scientists is that they engaged in too much theorising and not enough experiment and observation. This is simply untrue of Aristotle’s biological work. He was quite remarkable in founding an observational study of plants and animals. He spent time travelling throughout Greece, becoming acquainted with 500 species of animals, and making many careful and detailed dissections. His attitude to this study can be judged from the following: