II Formation and development of the theoretical system of TCM

TCM originated in the the Spring and Autumn period and the Warring States period, and its theoretical system was formed in the period from the Warring States to Qin and Han dynasties and developed in the Western and Eastern Jin dynasties and the Sui and Tang dynasties, the Song, Jin and Yuan Dynasties, the Ming and Qing Dynasties, as well as the modern and contemporary times. The development of the theoretical system of TCM at each stage has its own characteristics.

1.The formation of the theoretical system of TCM

The theoretical system of TCM was formed in the period from the Warring States to Qin and Han dynasties, and Huangdi's Canon of Medicine（Huan Di Nei Jing）（hereafter referred to as Canon of Medicine）,Classic of Difficult Issues（Nan Jing）,Treatise on Cold Damage and Miscellaneous（Shang Han Za Bing Lun）and Shennong's Classic of Materia Medica（Shen Nong Ben Cao Jing）marked its formation. These Chinese medical works laid a solid foundation for the formation of the theoretical system of TCM from the aspects of the basic theories, clinical syndrome differentiation, treating principles and methods and materia medica of TCM respectively.

Canon of Medicine（Nei Jing）is the earliest classic of the existing medical literature of China. The book is divided into Plain Questions（Su Wen）and Miraculous Pivot（Ling Shu）,collecting 162 papers.It elaborates systematically thestructure, physiology and pathology of human body, the diagnosis and treatment of diseases, health maintenance and other problems, forming the theoretical basis of TCM.Its main contents include visceral manifestations, meridians and collaterals, pathogenic factors, pathogenesis, diagnostic methods, treating principles, acupuncture and moxibustion, and decoctions, etc.It elaborates medical theories, and at the same time, discusses a series of major issues in the field of philosophy, such as the concept of qi, the relationship between human beings and nature, the relationship between body constituent and spirit in depth.Many contents in Canon of Medicine are beyond the world level at that time, for example, in the aspect of morphology, its records on the length of human bones and blood vessels, the size and capacity of internal organs are basically true, for instance, the ratio of the esophagus to intestine is 1:35,and in modern anatomy it is 1:37,which are very close;in the aspect of physiology, it has presented the idea that"blood circulation in the vessels is controlled by heart"and recognized that blood circulates in the blood vessels.The great theoretical contribution of Canon of Medicine（Nei Jing）lies in summarizing the medical experience and academic theory of the Spring and Autumn period, the Warring States period and Qin and Han Dynasties, establishing the unique theoretical system of traditional Chinese medicine and becoming the basis for the development of traditional Chinese medicine.

Classic of Difficult Issues（Nan Jing）contains a total of 81 questions and answers, so it is also known as"81 difficulties". It elaborates the body structure, physiology, pathogenic factors, pathogenesis, diagnosis, treating principles and methods, etc, and especially its contents about pulse diagnosis and acupuncture treatment are more detailed than Canon of Medicine（Nei Jing）.It is comparable with Canon of Medicine at that time, and also has important guiding significance for the clinical practice of later ages.

In the last years of the Eastern Han Dynasty, Zhang Zhongjing, a famous physician, further summarized the previous medical achievements and combined them with his own clinical experience, and finally wrote the clinical monograph Treatise on Cold Damage and Miscellaneous（Shang Han Za Bing Lun）on the basis of Canon of Medicine（Nei Jing）and Classic of Difficult Issues（Nan Jing）. It advocates diagnosing and treating exogenous diseases and endogenous diseases on the basis of six-meridian syndrome differentiation and visceral syndromedifferentiation, and thus it establishes the system of syndrome differentiation and treatment of traditional Chinese clinical medicine and the applying principles of syndrome differentiation, treating methods, prescriptions and herbs, which lays the foundation for the later development of clinical medicine.It was compiled into Treatise on Cold Damage Diseases（Shang Han Lun）and Synopsis of Prescriptions of the Golden Chamber（Jin Gui Yao Lue）by Wang Shuhe, a TCM doctor of Jin dynasty.

Shennong's Classic of Materia Medica（Shen Nong Ben Cao Jing）was written in the Han dynasty with Shennong's name. It is the first classic on materia medica in China, which records 365 kinds of drugs and summarizes systematically the pharmaceutical knowledge of the Han dynasty and before the Han dynasty.It divides the levels of drugs into upper, middle and lower based on health maintenance, treatment and toxicity, and divides the properties of drugs into cold, cool, warm and hot and the flavors of drugs into sour, bitter, sweet, acrid and salty according to the efficacy of the drugs.It lays the foundation for the formation and development of the theoretical system of Chinese materia medica of the later ages.

2.The development of the theoretical system of TCM

In the process of the development of TCM theories, the physicians of generations developed the theoretical system of TCM from different aspects by summarizing their own experience in clinical practice and researching systematically the theoretical viewpoints on the basis of Canon of Medicine（Nei Jing）,Treatise on Cold Damage and Miscellaneous（Shang Han Za Bing Lun）and other ancient classics.

2.1　The period of Wei, Jin, Sui and Tang dynasties

The characteristics of this period include two aspects:one is continuing to elucidate the theories;the other is emphasizing the importance of summarizing the clinical experience. In particular, the meridian and collateral theory, the pulse theory and the pathogenesis theory are further developed in this period.A-B Classic of Acupuncture and Moxibustion（Zhen Jiu Jia Yi Jing）,written by HuangfuMi, a noted physician in Jin dynasty, is the earliest monograph of acupuncture and moxibustion in China.It made in-depth discussions on the meridian and collateral theory and systematic exposition of visceral manifestations, meridians and collaterals, acupoints, specimens, nine kinds of needles, needling methods, diagnostic methods, syndromes and treating methods, etc.,and thus laid an important foundation for the development of acupuncture and moxibustion in later ages.Pulse Classic（Mai Jing）,written by Wang Shuhe, laid the foundation of the pulse theory and the systematicness and standardization of the methods of pulse diagnosis.It is the first monograph on pulse theory in China.Treatise on the Pathogenesis and Manifestations of All Diseases（Zhu Bing Yuan Hou Lun）,written by Chao Yuanfang, a physician in Sui dynasty, is the first monograph on the etiology, pathogenesis theory and syndrome theory of traditional Chinese medicine.It discusses in detail the causes and symptoms of many diseases, and thus has a significance for the later development of etiology and pathogenesis theory.Invaluable Prescriptions for Emergencies（Qian Jin Yao Fang）and Supplement to Invaluable Prescriptions for Emergencies（Qian Jin Yi Fang）were written by Sun Simiao, the famous physician in Tang dynasty.They give a detailed description of the medical theories, prescriptions, diagnostic methods, treating methods and health preserving by food before the Tang dynasty.Their rich contents can represent the advanced medical level and achievements of the flourishing Tang dynasty.They together are called Invaluable Prescriptions（Qian Jin Fang）,which is the first medical encyclopedia of China.

2.2　The period of Song, Jin and Yuan dynasties

The characteristics of this period are the rapid development of medicine, the appearance of many medical schools and the outstanding achievements, which have a great influence on the development of medicine in later ages. Many physicians combined their own practical experience with the achievements inherited from the former generations to make some innovations and present many original opinions, so that the traditional Chinese medicine had a new breakthrough in this period.In the Song dynasty, Qian Yi wrote Key to Therapeutics of Children's Diseases（Xiao Er Yao Zheng Zhi Jue）,which firstly advocated the treatment based on syndrome differentiation of zang-fu organs.Chen Yan wroteTreatise on the Three Categories of Pathogenic Factors and Prescriptions（San Yin Ji Yi Bing Zheng Fang Lun）and proposed the famous"theory of three causes",which made a more specific classification and summary of the causes of diseases.

In Jin and Yuan dynasties, Liu Wansu, Zhang Congzheng, Li Gao and Zhu Zhenheng made an important contribution to the development of the theories of traditional Chinese medicine, so they were known as"the four great medical experts in Jin and Yuan dynasties". Liu Wansu was influenced by the theory of yunqi（a theory for the ancients to study the climate change and to discover the relationship between human health and diseases）and so he emphasized that"six qi, including wind, cold, summer heat, dampness, dryness and fire（heat）,all can be transformed into pathogenic fire"and"excess of the five emotions-excessive anger, joy, grief, thought and fear can result in pathogenic heat".Therefore, the pathogenesis of fire and heat was further elucidated.Zhang Congzheng thought that the diseases were caused by pathogenic factors and a patient would be cured if the pathogenic factors were removed.He advocated using diaphoresis, emesis and purgation to remove the pathogenic factors.Li Gao presented the viewpoint that"dysfunction of spleen and stomach is the reason of many diseases",he thought that most of diseases were caused by the dysfunction of spleen and stomach.Zhu Zhenheng developed the theory of ministerial fire;he thought that the yin was often excessive while the yang was often deficient, so he advocated nourishing yin and purging fire.

2.3　The period of Ming and Qing dynasties

This is an important period for the academic development of traditional Chinese medicine. The contributions of the physicians and pharmacologists include two aspects:one is sorting out the medical achievements and clinical experience and compiling a wide range of medical books, classified medical books, medical collections and notes on medical classics, etc.The other is the formation of the warm heat theory and the school of warm disease, showing the significant innovation and invention in the medical theories and methods.

The school of warm tonification, represented by Xue Ji and Zhang Jiebin, emphasized the great importance of the spleen and kidney and formed the theory of life gate, in which the life gate was thought of as a place to hold yin and yang, fire and water, the root of the yin and yang of zang-fu organs and the hub of regulating yin and yang of the whole body. Li Zhongzi proposed the viewpoints that"the kidney is the origin of congenital constitution, while the spleen is the root of after-birth",making a new contribution to the development of the theories of traditional Chinese medicine, especially the theory of visceral manifestation.

The formation and development of the theory of warm disease is the innovative breakthrough in traditional Chinese medicine theory. The theory of warm disease originated from Canon of Medicine（Nei Jing）,Classic of Difficult Issues（Nan Jing）and Treatise on Cold Damage and Miscellaneous（Shang Han Za Bing Lun）,replenished and developed constantly by generations of physicians, and reached maturity in the period of Ming and Qing dynasties.In Ming dynasty, Wu Youke wrote Treatise on Pestilence（Wen Yi Lun）and first put forward the theory of"pestilential qi".He pointed out that plague attacked the human body by way of the nose and mouth.In Qing dynasty, Ye Tianshi wrote Treatise on Warm Heat Disease（Wen Re Lun）,developed the theory of defense, qi, nutrient and blood, and initiated defense, qi, nutrient and blood syndrome differentiation;Wu Jutong wrote Systematized Identification of Warm Diseases（Wen Bing Tiao Bian）and created triple energizer syndrome differentiation for warm diseases;Xue Shengbai wrote Chapter of Damp Heat Diseases（Shi Re Bing Pian）and proposed the original viewpoint that"damp heat diseases are not only different from febrile diseases but also different from warm diseases";Wang Mengying wrote Warp and Weft of Warm Heat Disease（Wen Re Jing Wei）.These books systematically summarized the pathogenic mechanism of the exogenous infectious febrile diseases, made a breakthrough in the traditional concept that"warm disease theory is developed on the basis of febrile disease theory",and created the syndrome differentiation and treatment of warm heat diseases mainly based on defense, qi, nutrient and blood syndrome differentiation and triple energizer syndrome differentiation, so that the warm heat disease theory has formed a complete theoretical system in the etiology, pathogenesis, and syndrome differentiation and treatment.In addition, Wang Qingren, a physician of Qing dynasty, attached great importance to anatomy, and he wrote Correction of Errors in Medical Classics（Yi Lin Gai Cuo）,in which he corrected the errors of human anatomy in the ancient medical classics and developed the theory of blood stasis causing diseases and the treating methods for diseases caused by blood stasis, making a certain contribution to thedevelopment of the basic theories of TCM.

2.4　The modern period

In modern period, a new trend of combing traditional Chinese medicine and western medicine and the scientification of traditional Chinese medicine has taken shape. With the widespread use and development of western medicine, many traditional Chinese medical workers with modern scientific thoughts, such as Tang Zonghai, Zhu Peiwen, Yun Tieqiao and Zhang Xichun advocated integrating Chinese medicine and western medicine because both of them have their own advantages and put forward a series of ideas on how integrate them in theory and practice.Records of Integration of Traditional Chinese and Western Medicine（Yi Xue To Zhong Zhong Can Xi Lu）,wrote by Zhang Xichun, is a masterpiece of the integration of traditional Chinese and western medicine.

After the founding of the People's Republic of China, the government has promoted the integration of traditional Chinese medicine and western medicine, and then advocated studying traditional Chinese medicine with modern multi-disciplinary approaches. Therefore, the theoretical development of traditional Chinese medicine in this period has the three main achievements:First, the theories of traditional Chinese medicine have become more systematic and standardized after sorting researches, and a series of national textbooks have been complied and published;Second, a variety of modern scientific methods have been applied for making researches of traditional Chinese medicine, and many scientific achievements have been attained and many monographs have been written;Third, the thinking way of constructing the theoretical system of traditional Chinese medicine has been studied, and the origin of the concepts in the theories of traditional Chinese medicine and the ways of further developing and innovating traditional Chinese medicine have been discussed.