On textual and contextual position of the ophthalmological treatise of bodhisattva nāgārjuna.

Medical knowledge in India began to be introduced to China in earliest from the Later Han Dynasty period to the times of Wei-Qin and South & North Dynasties. This is proved by many Buddhist medical books appeared in those days. Of the contents of Indian medicine, the theory of four major elements affected Chinese medicine more than did the theory of body fluids. Based on the theory of four major elements that was began to be introduced in Fú shuō fú yī jīng, an attempt to establish a new medical system was made in Zhŏu hòu băi yīfāng written by Táo Hóng-jĭng and Sūn Sī-miăo who tried to develop etiology further but could not achieve any great outcomes. Unlike the foregoing situation, Indian medicine aroused a large echo in China in the field of ophthalmology with ophthalmological knowledge mentioned in Suśrutasa hitā and 'Jīnzhēn-shù'(cataract couching) introduced as a surgical treatment of cataract. The Suśrutasa hitā which is one of the three major texts of Indian medicine contains additional information on surgical operations not introduced in the Carakasa hitā. The technique of cataract surgery was particularly popular in the Tang and Song dynasty periods in China under the name Lóng shù pú sà yăn lùn(The Ophthalmological Treatise of Bodhisattva Nāgārjuna) or Lóng shù lùn and was even designated as a subject to educate medical officers. While the original text of Lóng shù pú sà yăn lùn was not handed down, the first testimony that show the trace of the introduction of this text into China was the Tiān zhú jīng lùn yăn mentioned in Wài tái mì yào(Arcane Essential from the Imperial Library) written by Wang Tao. Long shàng dào ren who was mentioned as the compiler of the book is assumed to be Lóng shù. Although Tiān zhú jīng lùn yăn introduced anatomical knowledge about the eyeball that could have not been in the traditional Chinese medicine, this book has only limited quantity of information in this regard. Thereafter, Tài píng shèng huì fāng (Holy Prescriptions for Universal Relief) compiled by a national agency at the beginning of the Song Dynasty period introduced Lóng shù pú sà yăn lùn without clear indication of the reference. Contemporary with this book, many ophthalmological books such as Mì chuán yăn kē lóng mù lùn(Longmu's Ophthalmology Secretly Handed Down) were published. As Chinese culture was spreading out into surrounding countries, medical knowledge was also introduced to Korean peninsula and Japan. The ophthalmological knowledge contained in Lóng shù pú sà yăn lùn was also reflected and some parts of it were introduced in I shin bō in Japan. Based on the policy decision of King Sejong, the fourth king of Joseon Dynasty, large scaled promoting projects of medical knowledge was established. It is notable that the Ui bang ryu chwi compiled as a result of the synthesis of the medical treatises available at that time initiated by King Sejong contained a considerable part of Lóng shù pú sà yăn lùn in reedited form that had already passed into oblivion in China. The intellectuals in Joseon Dynasty who participated in the compilation of Ui bang ryu chwi not only indicated that Lóng shù pú sà yăn lùn was a medical text published in the times of Wei-Qin and South & North Dynasties in China but also clearly indicated the textual reference and left the original text for later generation without modifying the contents. According to the Ui bang ryu chwi, the Lóng shù pú sà yăn lùn indicated that the core causes of eye diseases were heat, winds, and three body fluids(trido a) and contained the analyses of symptoms, related treatments, and several analyses of wrong treatments. In addition, Lóng shù pú sà yăn lùn explained diverse eye diseases through more than 30 medical treatments. In particular, this book accurately described golden needle acupuncture for treatment of a Nèi-zhàng understood to be cataract. Therefore, this book is a significant textual record in the history of ophthalmological medicine in East Asia. Along with the golden needle acupuncture which is a method of removing the crystalline lens in which white turbidity occurred by stabbing the eyeball with a needle, traces of Indian medicine that had been already lost in China were clearly indicated in Lóng shù pú sà yăn lùn kept in the Ui bang ryu chwi. In particular, the book indicates that the eyes were directly correlated with the brain and that to treat the internal disorder, treating the brain that lost stability due to heat and bodily wind was indispensable; these are the traces of Indian influence. This textual source demonstrates a case of knowledge exchange in field of medicine with concrete cases of the encounter and clash between the standpoints of understanding human body.