从来考古方权量者，人各言殊，大半误以汉制当之耳！岂知经方传于仲景，而不自仲景
始。
《外台》卷一谓桂枝汤为歧伯授黄帝之方，而分两与《伤寒论》悉同。可见经方传自上古，
所用权量，亦上古制，非汉制也。《千金》备详神农秤及古药升之制。盖古医权用神农、量
用药升，于一代常用权量外，自成一例。仲景而下，讫于《外台》，所集汉晋宋齐诸方皆然
。迨隋唐人兼用大两大升，而后世制方遂有随代为轻重者，此古权量所由湮也。国朝吴王绳
林所考，宗法《千金》，参以考订，定为古一两，当今七分六厘；古一升，当今六勺七抄。
洵不刊之论，无间然矣。其书载在《吴医汇讲》中。
夫欲学医，必先读无方之书，则莫善于巢氏《病源》焉。《病源》引申经意，别类分门
，比
《灵》、《素》为易知，亦较《灵》、《素》而易入。习之既久，遂乃上探《灵》、《素》
，兼读《难经》、《甲乙经》二书以疏之，明乎经络脏腑之源，达于望闻问切之故，而于向
者之所得，益觉融会贯通，而明体者渐渐达用矣。然后读有方之书，《玉函》、《伤寒》、
《金匮》是也。读三书尤必兼资《脉经》，以稽其异同，披本草（须用《证类本草》）以观其
方法，盖临病之舟楫在焉。然《伤寒》之理，未许其遽通也，又必浸淫乎《肘后》、《千金
》及《翼》、《外台》四书，斟酌乎《本事方》、《百证歌》、《九十论》、《明理论》等
说，参互考订，以徐俟其悟，殆另有一境矣。大抵医者之于伤寒，其致力每在杂病未究之先
，其得心转在杂病悉通之后，不亲历者不知也。溯流穷源，其事止此；神而明之，存乎其人
。至于《圣济》、《局方》以下，则学成后读之，亦足扩聪明而炼识力，不必概屏之以自隘
也。
Since ancient times, those who have researched the weights and measures of ancient prescriptions have offered varying accounts, mostly erroneously applying Han dynasty standards. How could they know that while the classic prescriptions (Jingfang, classical formulas) were transmitted through Zhang Zhongjing, they did not originate with him?
Volume 1 of *Waitai Miyao* (Secret Essentials of the Outer Cabinet) states that Guizhi Tang (Cinnamon Twig Decoction) was a formula transmitted by Qibo to the Yellow Emperor, and its dosage matches exactly with that in *Shanghan Lun* (Treatise on Cold Pathogenic Diseases). This demonstrates that classic prescriptions were inherited from antiquity, and the weights and measures used were also those of antiquity, not Han dynasty standards. *Qianjin Yaofang* (Essential Prescriptions Worth a Thousand Gold) details the systems of the Shennong scale and ancient medicinal sheng (a unit of volume for herbs). Generally, ancient physicians used the Shennong scale for weighing and medicinal sheng for measuring herbs, establishing a system distinct from the common weights and measures of each era. From Zhang Zhongjing onwards, up to *Waitai Miyao*, all collected prescriptions from the Han, Jin, Song, and Qi dynasties followed this pattern. It was only when Sui and Tang practitioners began using larger liang and sheng units that later prescription formulations varied in weight and volume across different dynasties; this is how ancient standards of measurement gradually became obscured. Wu Wangshenglin of our dynasty conducted research based on *Qianjin Yaofang*, supplemented by critical examination, and determined that one ancient liang equals approximately 0.76 qian today, and one ancient sheng equals approximately 6 shao and 7 chao today. This is indeed an unassailable conclusion, beyond reproach. His work is recorded in *Wu Yi Hui Jiang* (Collected Lectures of Wu Physicians).
To learn medicine, one must first read texts without specific prescriptions; none is better than Chao Yuanfang's *Zhubing Yuanhou Lun* (Treatise on the Pathogenesis and Manifestations of All Diseases). *Zhubing Yuanhou Lun* elaborates on the meanings of classics, categorizes diseases, and is easier to understand and more accessible than *Ling Shu* (Spiritual Pivot) and *Su Wen* (Basic Questions). After studying it for a long time, one can then explore *Ling Shu* and *Su Wen*, and simultaneously study *Nan Jing* (Classic of Difficult Issues) and *Jia Yi Jing* (A-B Classic) to clarify them, thereby understanding the origins of meridians and zang-fu organs, and mastering the principles of inspection, auscultation-olfaction, inquiry, and palpation. Consequently, previous knowledge becomes integrated, and understanding the fundamental principles gradually leads to practical application. Only then should one read texts containing prescriptions, such as *Yuhan Jing* (Jade Box Classic), *Shanghan Lun*, and *Jingui Yaolue* (Essential Prescriptions of the Golden Cabinet). When studying these three books, one must also consult *Maijing* (Pulse Classic) to examine similarities and differences, and review *Bencao* (Materia Medica, specifically *Zhenglei Bencao*) to observe therapeutic methods, as these serve as essential tools for clinical practice. However, the principles of *Shanghan Lun* cannot be mastered hastily; one must immerse oneself in *Zhouhou Beiji Fang* (Handbook of Prescriptions Kept in the Sleeve for Emergencies), *Qianjin Yaofang*, *Qianjin Yifang* (Supplement to Essential Prescriptions Worth a Thousand Gold), and *Waitai Miyao*. One should also deliberate on theories from *Banshi Fang*, *Baizheng Ge*, *Jiushi Lun*, and *Mingli Lun*, cross-referencing and verifying them to await gradual enlightenment, which will likely open up another realm of understanding. Generally speaking, a physician's effort regarding cold damage often precedes their deep study of miscellaneous diseases, yet their true insight often comes after mastering miscellaneous diseases—a truth known only through personal experience. Tracing the source ends here; divine comprehension depends on the individual. As for texts below *Shengji Zonglu* (General Records of Holy Relief) and *Tai Ping Hui Min He Ji Ju Fang* (Imperial Bureau of Medicines Formulary), these should be read after achieving proficiency; they are sufficient to broaden intelligence and refine judgment, and need not be entirely rejected to avoid self-limitation.