The Oath of Hippocrates fulfilled in the Integration of Traditional Chinese Medicine in today's standard medicine
Hippocrates of Kos (460-370 BC), was a physician of Athens and various Greek city-states who established schools of medicine and became known as the father of Western medicine, mostly because of his fame and the 70 or so books that he wrote. The concepts that he wrote of, empirical reasoning and the use of natural philosophy and patterns applied to a careful individualized medical history and exam, as well as a categorization of diseases that should guide treatment, was in use well before Hippocrates, but Hippocrates was successful in addressing concepts of natural science or philosophy, popular at the time in the Greek cultures because of such esteemed thinkers as Socrates, Plato, Aristotle, and Hippocrates' patient and teacher, Democritus. Hippocrates writings successfully addressed many of the popular issues in medicine, ritualized beliefs in spriritual causes of disease and the proclamation that the physician should first understand philosophy and natural science to effectively cure. These two issues were diametrically opposed, and represented common schisms in society. Hippocrates explained that the physician first needed to be grounded in a thorough knowledge of practical matters, anatomy, physiology, and the concepts of disease, and then could apply the concepts of spirit as well as the abstract sciences found in philosophy.
The most famous part of Hippocrates' large corpus of medicine and medical philosophy was the Hippocratic Oath, which survives today in some form in modern medicine. The oath, a statement of medical ethics, is usually abbreviated to the statement: First, do no harm. In actuality, the oath used by many medical schools is believed by historians to be inspired by Hippocrates statements, but actually composed by the Pythagorean schools. In this oath of the physician, many ethical considerations are mentioned, including never prescribing lethal drugs if asked to end a life, to never give medicines to cause abortion, to live a pure life and never engage in sex with a patient, to never perform surgeries outside of one's specialty, to observe patient confidentiality, to support one's teachers financially, and lastly, to utilize dietary medicines and holistic therapies that do no harm, i.e. have no side effects, whenever possible. If we actually read Hippocrates' works, which is fairly easy now with the aid of the internet, we see that Hippocrates indeed addressed all of these issues, only not in one oath or paragraph. The last issue mentioned in the oath, which is the basis for do no harm, is very important to medical pratice today, and a careful reading of Hippocrates shows that he was very concerned that physicians of his time not abandon practical means of restoring health with dietary regimens, benign herbal medicines, lifestyle changes, patient instruction in therapeutic activities, and physiotherapies, all of which he practiced in his treatment. Hippocrates made clear that only after this conservative care was tried, should more radical means be used in most circumstances, in order to avoid the injury from toxic chemistry and surgical procedure.
The principles in the work entitled the The Oath of Hippocrates are found in Hippocrates' work called On Ancient Medicine, in which he lays out his arguments for how a physician should view medical science. In this work, Hippocrates first makes clear that those before him that wrote of medical theory generally narrowed the focus of the basic causes of disease down to simple fundamental causes, much as in the philosophical schools of the age, which were seeking to understand the basic building blocks, or stuff of the universe, of nature, or of reality. Hippocrates warned against this type of reasoning in medicine, stating that to so narrow one's framework would take away from the ability of the physician to consider all possibilities and provide the best therapy for each patient. The physician needed to always acquire more knowledge and to incorporate, or integrate, all of this medical knowledge into the therapy, for the good of the patient. While adopting more narrow schools of thought may work for the philosophers as they sought the stuff of life, or the occultists, as they tried to understand the intangible, a physician needed to be rooted in a broad understanding of everything that could apply to helping each individual patient, because the individual with injury or disease was not concerned with the most correct view of nature or of God, but only of getting well.
Hippocrates makes clear in this work that it is the responsibility of the physician to explain medical problems in clear terms so that even the illiterate patient understands what is wrong with them and what caused the problems. He also stated that the physician must understand that modern habits of diet and lifestyle, or environmental concerns, naturally preclude us all to some ill health, for when we abandoned a purely natural existence like the other wild animals on the planet, we created causes for disease. These must be analyzed and more natural diets and lifestyles suggested to the patient to improve their health. In like manner, when those that pursue athletic excellence learn of techniques to improve performance, these are adopted, and so should techniques of improved diet and lifestyle for the patient population. Hippocrates noted that if all persons were to consume the healthiest of diets, that most disease would not happen, and so the subject of nutritional medicine should be an important part of each physician's practice. In other words, Hippocrates supported Naturopathic medicine.
Not only did Hippocrates warn against physicians ignoring ancient medicine, or principles of healthy diet and lifestyle, but he also warned against adopting ideas of dietary medicine and therapeutic regimens that were not individulized to each patient. He noted that prescribing one type of dietary regimen to a problem will work for one patient, but not the next, and so a method of individualized diagnosis and patterning was suggested. Hippocrates went to some length in this treatise to explain that when a patient adopts unhealthy habits and comes in to treat, that many physicians resort to pure hypotheses to cure, using medicines that act against the problems seen in the patient, countering imbalances with their opposites, etc. This describes the evolution of allopathic medicine, using chemistry to stop specific physiological disease mechanisms. Hippocrates explains that this patient may be weakened by their condition and not respond in a healthy way to this treatment, but may suffer. On the other hand, he notes, if the patient is instructed to correct the underlying causes of their condition, adopting healthier diet and habits in life, they may regain health even without these more sophisticated medicines. Hippocrates is advocating that we always look to a more holistic and natural medical tactic to complement the new allopathic medicines that we conceive.
These ideas of Hippocrates mirror precisely the advice given in the foundation texts of Traditional Chinese Medicine. In the main text, called the Nei Jing de Huang Di, or Complete Text of Corporeal Medicine as presented to the Founder of Civilized Medicine, Huang Di (in a metaphorical conversation), the reasons why physicians should not ignore ancient medicine, and the integration of naturalist principles as a complement to new findings, ideas, and methods in medical science, are presented in the beginning of the text, and again at the end of the text in the chapters on medical ethics. These ideas of Hippocrates stated above are identical to the concepts presented in this great work put together from various physicians writings by the original Han dynasty, as an official text in about 400-300 BC, the exact time of Hippocrates writings. Is this a coincidence? Or, was there a common foundation as well as an exchange of information and ideas between ancient civilizations that we have underestimated. Perhaps we should review our history with a more global perspective, and begin to apply this knowledge to the question of integrating holistic Complementary Medicine into standard medical practice for the benefit of public health and the best outcome for each individual patient.
Comparisons of early Greek medical scientific ideas and those of the Chinese Taoists
While the ideas of the Chinese Taoists in Traditional Chinese Medicine (TCM), using terms such as Yin, Yang, Qi and Jing, which are difficult to translate directly into the European languages, seem to be presenting a foreign set of ideas in medicine, these concepts are very similar to those of the ancient Greek founders of our modern medicine in the West. In the European medical history, Greek physicians, such as Hippocrates, laid the conceptual framework for Galen, and established a medical foundation that we still utilize today. It is useful in an age of Complementary Medicine to try to understand the similarities and likenesses of the Taoist and Greek foundations, rather than to focus on the differences, if we really are to achieve a blending, or complement, of TCM with modern medicine.
The difference between the European and Chinese cultures concerning medicine is more a matter of reverence and irreverence for the fundamental concepts of natural science that laid a foundation for medical practice, and so a Traditional European Medicine has not survived while Traditional Chinese Medicine is flourishing. Since the 17th century, the medical community of Europe has vigorously ridiculed the past as new medical concepts and technology are created, while in China, the culture has nurtured its roots even as the branches have grown. This has created a more vigorous science and business of chemistry in the West than the East, but now the global blending of a preserved protochemistry and public health regimen from the East with the more technological advances from the West is creating a new medical paradigm. Concepts of natural medicine are needed in the West, even as new chemical medicines are being developed. A greater understanding of the natural sciences, and a quantum, or holistic, view of healthy homeostatic mechanisms, is needed to decrease the side effects of purely technological advancements. We also need to take the next leap forward in medical technology, and create medicines that restore healthy function, rather than block unhealthy processes. Restoration of healthy function is a fundamental concept that guides the Taoist TCM even as it refines its science with modern research. This same concept was also evident in the Greek roots of modern Western medicine.
Galen, who is widely attributed as the founder of modern medical scientific method and concept in Europe, wrote that the best physician is also a philosopher, and was well studied in the ideas of Aristotle. In fact, many of the great Greek philosophers that we continue to revere today practiced as physicians, mirroring the histories of many of the great Taoist philosophers. A philosopher was a person considered to be seeking wisdom, or understanding of natural science, physical and metaphysical. Hippocrates was purported to be the physician to Democritus, one of the most important philosophers and natural scientists of the early Greek civilization, and imparted much medical knowledge to Democritus, who laid the foundation for the theories of the atomic structure of matter and energy in about 420 BCE. Hippocrates then considered Democritus to be his teacher, and many of the concepts of modern medicine originating in the ideas of Hippocrates, came from the genius of Democritus. Hippocrates declared that physicians must convert or insert wisdom to medicine and medicine to wisdom. It is well documented that Democritus was well travelled, especially to the Persian empire, where he sought out other famous philosophers, who had contact with the great Taoist philosophers of ancient China.
Greek civilization arose from the cults of Bacchus and Orpheus. Orpheus himself, like many of the famous Greeks, was historically both a common man and purportedly a physician, while in ritual cults, a god. Legend has it that Orpheus taught humanity the arts of medicine. These god legends were a means of popularizing historical figures so that the history would be passed on in popular culture, and the Greeks certainly separated the ideas of the popular gods from their belief in the creator God. The Greek gods of legend did not create our world at all, but merely inhabited it, and the legends were a means of promoting a political cult around the ideas of famous figures, that proved to be powerfully expedient to the aims of political figures, especially in the more democratic communities of Hellenic Greece, where popular support was needed to maintain power. Aristotle, who promoted a more logical view of history, continued to develop the Orphic traditions while denying that the god Orpheus actually existed. Bacchus, or Dionysus, another popular god cult figure in Greek culture, was famous for his alcoholic elixirs, some of which transported the followers of Bacchic ritual to out of body experiences, while Orpheus promoted more tempered and spiritual rituals and health practices.
We see that medical science played a significant role in the fashioning of Greek civilization and philosophy. The need to understand the workings of the body, and the need to understand nature and life itself, were integral to the society. From the study of medicine came the most significant revelations about nature and the origins of life. The great philosophers formed schools of learning, and many felt that to truly know medicine and curing, one needed to understand natural law and philosophy. Hippocrates broke with this concept to some extent, as he was not truly a philosopher, but did study with philosophers. Hippocrates stated that the best way to understand nature was to study medicine, and that the knowledge of natural science is attained only by comprehending the whole subject of medicine properly. In China, many Taoists also had taken up the study of medicine, and contemplated nature and natural science by observing the patterns of nature in medicine. Today, Traditional Chinese Medicine is still taught as a Taoist science, and the underlying maxim is that the patterns observed in nature apply to the body, and that the relationship of the individual to the environment is important in the understanding of disease. To the Taoist, bringing the patient back into balance with themselves and with nature and their environment, is to restore natural homeostasis and insure optimal health. TCM is a practice of evaluating all aspects of pattern and imbalance in physiology and anatomy, as well as the external forces of activities, diet, pathogens and toxins on the balanced function of the patient.
The exchange of scientific and philosophic ideas along with commerce, and the common development of medical science in China, Persia and Greece
In the fourth century B.C., the Macedonian Empire of Alexander the Great, student of Aristotle, stretched to the Hindu kingdoms, and trade along the Silk Road brought ideas West to the Greek trading states. The Silk Road was composed of 7000 miles of ancient trade routes that helped establish the great civilizations of China and Persia, and made the small city states of Greece, that focused on trade, rich. These routes of commerce inspired the young Alexander to travel farther with his military than any other leader in the Hellenic world before him, and to preserve the cultures that he conquered, instead of destroying them, incorporating ideas, science, religion, and philosophy, to create greater civilizations. The name, the Silk Road, came later in history, with the development and popularity of silkworm thread, but the trade routes preceded the silk commerce by thousands of years. Sea commerce was also extensive, with the Bible documenting the importing of gold and hardwood from India by sea in the time of Solomon as early as 1000 BCE (Kings;11;ix,21). By 700 BCE, overseas trade was extensive, and many artifacts document the exchange of goods and wealth between China and Mesopatamia, via India. By the fifth century BCE, there is documentation of the importing of rice and peacocks from India to Greece.
The riches exchanged between civilizations were composed of more than metals and foods, with information and concepts being invaluable. Civilizations needed to believe that the leaders they followed were superior in intelligence and understood the mysteries of life. So, along with new metals and technology, foods and medicinals, fabrics and gems, came a trade in knowledge and understanding. Trade from the Fertile Crescent of Mesopotamia to Mongolia was well documented as far back as 6000 BC, and it is proven that domesticated goats and sheep were brought from Southwest Asia to Egypt by caravan in the 7th millenium BCE. By the 4th millenium BCE, the gemstone lapis lazuli was much traded from its only known source, in what is now Afghanistan, to Egypt. By the 2nd millenium BCE, this lapis lazuli, and jade from nearby mines, was flowing to China. The Persian Royal Road ran from the Tigris to what is now Turkey, and was maintained by the Achaemenid Empire, or Persian Empire, that extended into Europe, from 500 to 300 BC, before the defeat by Alexander. The most famous interactions between this empire and Greece were the great battles between Xerxes and the Greeks.
Although European history omits mention of the great Chinese and Hindu civilizations, the fact of trade and contact are evident, and the influence of the great Taoists from China in the thought and science of the Hellenistic culture is also evident. By the time of the Roman Empire, frequent trade missions from China to Bactria and Parthia, on the eastern edge of the Roman Empire, are well documented. Before this, in the time of Socrates, accounts in the biblical Book of Esther speak of dispatches sent from Susa, east of the Tigris, to the kingdoms of India and Kush. In recent years, excavations have uncovered the Caucasoid Tarim mummies in the area of Loulan along the silk road, dating to 1600 BCE. This suggests at least contact between East and West, if not a common ancestry to many of the peoples.
The similarities between the Medical Sciences of Hippocrates and the Taoists
The history of Greek medicine was built on the traditions of Egypt, India, China and Mesopotamia, with two major medical movements, the cult of Asclepius, and the rational medicine of Hippocrates. Asclepius was the god of medicine, son of Apollo, whose emblem was the caduceus, or winged staff encoiled by two snakes, which is still used by the medical profession today. The Greeks used the legends of the gods freely, and Asclepius was actually a Greek physician of about 1200 BCE. By 400 BCE, Hippocrates had established schools of rational medicine based on natural law, with a theory of humors and elements that was very similar to the Taoist theories of Traditional Chinese Medicine. Hippocrates emphasis on clinical observation of signs and symptoms, with a differential diagnosis, all based on patterns observed and chronicled empirically over time, was also nearly identical to the Taoist system, as well as Egyptian theories and practice. Treatment in Hippocrates' system was based on restoring balance, or homeostasis. This too was identical to the Taoist approach. There was a great emphasis on disease relating to seasonal patterns, with diagnosis emphasizing elements such as Damp, Phlegm, Cold, Heat, and Dry, exactly as the diagnostic theories of the Taoists.
Is it a coincidence that the earliest surviving copies of the Taoist Nei Jing, or Canon of Internal Medicine, dates also from about 400 BCE? The striking similarity of this text to the concepts of Hippocrates are remarkable. This is a time when written manuscripts became more popular, and were obviously a valuable commodity in trade. It was also a time when written languages became more universal, and scholars of various cultures were knowledgeable of various written languages. Not only oral knowledge, but written knowledge as well, was passed between cultures in the time of Democritus and Hippocrates. Historians doubt whether there was direct contact between the great Chinese civilizations and the Greeks, but was this really even necessary for the exchange of important ideas and concepts? In Greek history, it was documented by Apollonius Rhodius, the author of the Argonautica, that Orpheus also travelled extensively. Pindar, and other historians, tell us that Orpheus was born of the king of Thrace, in northern Italy, in Pieria, and was raised in Parnassus, in southern Italy, by his mother. Thrace was a kingdom near what is now Turkey, and Orpheus purportedly ruled the Cicones, a coastal civilization, mentioned in Homer's Odyssey. He travelled to the island of Lesbos, and on to Asia Minor, or Persia, as the Cicons were a seafaring civilization. Orpheus is considered to be the historical figure that brought the Greek civilization the arts of medicine.
So it is established that Hippocrates laid the foundations for many of the ideas and practices of European medical science, and that Hippocrates was taught philosophy and natural science by Democritus, who had travelled extensively to accumulate his body of wisdom and understanding. It is also established that many of the basic ideas of Hippocrates, the elements and humors, the fundamental naturalist universals of Cold, Heat, Wind, Damp, Dry and Phlegm, and even the immaterial atomic energetic structure of matter (mirroring the concept of Qi), are nearly identical to the concepts in the Taoist medicine.
The Greek legendary god of medicine was Asclepius, whose legend originated on the island of Kos, or at least the most well known temple of Asclepius was located on Kos, where Hippocrates purportedly studied and began his career. The legend has it that Asclepius was the son of Apollo, and had 5 daughters, named Health (Hygieia), Medicine (Iaso), Healing (Aceso), Healthy Glow (Agleaea), and Universal Remedy (Panacea). A sixth daughter, the Serpent-bearer (Meditrina) was also important in the later legend, as Asclepius was purported to use serpents in ritual and healing practices. The famous rod of Asclepius that is still used as a symbol of the modern medical practice, has a snake entwined around a rod, and another medical symbol, the caduceus, a symbol of Hermes, has twin snakes entwined around a rod, or staff. Asclepius was purportedly killed by Zeus for raising Hippolytus from the dead, and Justin Martyr, a famous early Roman Christian, stated that the legends of Asclepius foreshadowed the story of Christ, both in the healing legends and in the rising from the dead. As is the case in history, another medical legend with a similar name, Asclepiades of Bithynia (124-40 BCE), also became famous as the first important Greek medical scientist to teach in Rome. Asclepiades also adhered to the atomic theory of Democritus, and the concepts of Hippocrates. He purported that the body was made up of molecules, and that alteration of the form or position of the molecules caused disease. Although a famous surgeon, he favored the more naturalistic, or holistic, therapies, incorporating nutritional medicine, physiotherapies, and exercises whenever possible. He was perhaps the first physician to distinctly classify diseases as chronic or acute.
Hippocrates is credited for many important concepts pertinent to modern medicine, as well as his theories of fundamental elements and humors. There are over 70 books attributed to Hippocrates, and his description of the history and physical exam, with a method of differential diagnosis, is still an essential concept. He was a famous teacher of medical science, and saved Athens from a devastating plaque epidemic utilizing herbal medicine. He realized the complexity of human physiology and disease, and instructed his students to at least do no harm as a general rule in treatment, rather than to try toxic remedies too quickly. He wrote of the pathogens in wounds as a cause of spreading disease, of obesity as a health risk, of neurological diseases such as epilepsy as a physical illness and not a possession by demons, and described brain surgery, stating that if the surgeon cut into the temporal lobe, that spasms would occur on the opposite side of the body. His descriptions of clinical evaluation of central nervous system disorders, and the humanistic and individualized approach to therapy that was needed inspired the modern field of neurology.
Hippocrates was adept with herbal medicine, and the first mention of salycylates from the willow bark, used for pain relief, was mentioned by him, and this became the first modern pharmaceutical, aspirin. He is also touted for his emphasis on holistic therapies in practice, combining nutritional medicine, herbal medicine, physiotherapies and mental exercises into a holistic regimen. While there is much to admire in Hippocrates' work in modern medicine, there is also currently a review of his conceptual and holistic ideas in medicine at a time that similar ideas from Traditional Chinese Medicine are being incorporated into standard medical practice in the form of Complementary and Integrative Medicine. Hopefully, the medical professions can apply the wisdom of Hippocrates to a renewed integration of allopathic and holistic traditional therapies.
Chinese contemporaries of Hippocrates and the Greek foundation philosophers
Zhuangzi (Chuang Tsu), 369 to 286 BC, along with Lao Zi, from roughly the same time period, are considered the founding philosophers of Taoism in China, and wrote extensively of many subjects, including medicine, at roughly the same time in history as the Greek philosophers that laid the foundation for European society and culture. The writings of Zhuangzi are perhaps as influential as the Dao De of Lao Zi, and led to an organization of thought and science that lasts till today. Lao Zi, a Zhou historian that captured Daoist thought succinctly in his writings entitled the Dao and the De, became a great influence on twentieth century humanist philosophy and the writings of Carl Jung. The Daoist naturalists established a holistic view of the world that carried over into the medical field, and the empiricism that dominates Daoist philosophy became a benchmark for objective diagnosis and treatment in medicine. Finally, in the twenty-first century, such empirical science and holistic perspective are beginning to again play an important role in medical philosophy and treatment.
Chunyu Yi was a famous physician of the Western Han empire of approximately 200 BC, and took the empirical sciences to heart, determining that each patient must be treated according to individualized diagnostic data.He established the habit of keeping patient case studies to elucidate this type of medical philosophy, and so advanced the field of differential diagnosis and disease classification.
Although there were many notable Chinese physicians during the Qin and Western Han dynasties contemporary to the age of Hippocrates, it was perhaps hundreds of years after the time of Hippocrates that a Chinese physician took advantage of the woodblock printing press, inexpensive paper, and the invention of true ink from lamp-black, and published a reworking of the basic tenents of medical ethics and the modern social views of the practice of medicine. The famous Daoist physician philosopher, Sun Si Miao, is now known as the “Hippocrates of China“, as well as the “King of Medicinals”. Although his ideas were not new to medical ethics and organization in China, his seminal works clearly defined these medical ethics and reorganized clinical practice guidelines and theories to better support the modern social framework in China emerging from the writings and theories of Lao Zi and Confucius. Sun Si Miao proclaimed that family practice, female health, and the realm of obstetrics should take a primary role in medical practice to better support the social and family well-being.
Sun Si Miao also proposed the ethics of community medicine shaped by the developing Daoist practices of his time, including emphasis and better preventive medicine through public dietary guidelines and calisthenic practices, promoting a practical theory translated as Nurturing Life, or yang sheng. Sun Si Miao advised physicians to adopt a more Daoist approach to practice and achieve a focus in the clinic that needed to be separated from the thoughts of profit or personal life, consistent with the developing Buddhist ideals embraced by the Daoists. He wrote that the physician must “quiet his spirit and will, be free of wants and desires, and must first develop a heart full of great compassion and empathy, pledging to devote himself completely to relieving the suffering of all sentient beings (rich and poor and of any ethnic background).” Sun Si Miao advised that when patients came to the physician, this physician should not inquire whether they are from the noble or low class, wealthy or poor, and matters of age, beauty, ethnicity, intelligence, education, or even whether they are likable or unliked, friend or foe, should not be a consideration in diagnosing and treating their illness or injury. The physician “must treat all of them exactly the same, as if they were the closest relative.“ He also advised that the physician must never “look to the front while turning around to cover his back“, or worry about personal fortune or misfortune. Doing what is right in treatment should supersede any thought of the consequences of failure and the accusations of malpractice, or the risks entailed to his own health and well being when delivering care. He must not worry about fatique, hunger, thirst, sleep or the dangers of travel, but only about the well-being of the patients. Sun Si Miao wrote that “acting like this, he can serve as a great physician for the masses; acting against this, he is a gigantic thief to all sentient beings.”
Today, these theories of social medicine are still being promoted by such organizations as the Red Cross, Physicians Without Borders, and Physicians for Social Responsibility. Many licensed acupuncturists have also gone into community medicine and tried to provide their specialty to the poor, AIDS victims, and now even to refugee camps and victims of natural disasters around the world. These noble ethics have their root in our medical history, both European and Chinese.
Information Resources
- Hippocrates work on ancient medicine and adoption of Complementary Medicine and conservative holistic therapies can be read in this translation of his work by the University of Adelaide of South Australia: http://ebooks.adelaide.edu.au/h/hippocrates/medicine/index.html
- Harvard Medical School study on the CNS modulatory effects of acupuncture stimulation. http://www3.interscience.wiley.com/journal/70000102/abstract?CRETRY=1&RETRY=0
- 1998 fMRI study of distal acupuncture stimulation and physiological effects in the brain at the University of California Irvine can be seen at http://www.pnas.org/content/95/5/2670.full.pdf?ck=nck
- The study designed in Britain to eliminate study design bias can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/18054724
- A German journal article discussing problems with acupuncture trials is very illuminating from a number of perspectives: http://www.karger.com/ProdukteDB/produkte.asp?Aktion=ShowPDF&ArtikelNr=110416&Ausgabe=234157&ProduktNr=224242&filename=110416.pdf This article is titled Forschende Komplementarmedizin 2007;14:371-375 Journal Club - Acupuncture for Hypertension: A Tale of Two Trials, and you may need to scroll down the page to Further Sections 371 Journal Club and click on the Article PDF Free Access. If this link fails, you may try searching under this title.