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。
自古以来考证古方剂量的人，说法各不相同，大多错误地用汉代的制度来对应罢了！哪里知道经方传承自张仲景，但并非从张仲景才开始。
《外台秘要》卷一称桂枝汤是歧伯传授给黄帝的方子，其分两与《伤寒论》完全相同。可见经方传承自上古，所使用的权量，也是上古的制度，而非汉代的制度。《千金要方》详细记载了神农秤及古代药升的制式。大概古代医家称重使用神农秤，量取药物使用药升，在一代常用的权量之外，自成一套体系。从张仲景以下，直到《外台秘要》，所收集的汉、晋、宋、齐各代的方剂都是这样。等到隋朝和唐朝人兼用大两大升后，后世的制方便有了随着朝代更替而轻重不同的情况，这就是古法权量逐渐湮没的原因。本朝吴王绳林所考证的内容，效法《千金要方》，参考考订，确定古一两相当于当今七分六厘；古一升相当于当今六勺七抄。这确实是不可磨灭的定论，无可挑剔了。他的著作收录在《吴医汇讲》中。
想要学习医学，必须先阅读没有具体方剂的书籍，那么没有比巢元方的《诸病源候论》更好的了。《诸病源候论》引申经典经义，分类别门，比《灵枢》、《素问》更容易理解，也比《灵枢》、《素问》更容易入门。学习久了，进而向上探究《灵枢》、《素问》，同时阅读《难经》、《甲乙经》两书以疏通文意，明白经络脏腑的源头，通晓望闻问切的原理，对于之前所学的知识，更加觉得融会贯通，从而由明体（掌握根本理论）渐渐达到达用（灵活运用）。然后阅读有具体方剂的书籍，《玉函经》、《伤寒论》、《金匮要略》就是这类。阅读这三本书尤其必须兼资《脉经》，以考察其异同，披阅本草（必须使用《证类本草》）以观察其治疗方法，因为这是临证治病的关键工具。然而《伤寒论》的道理，不允许急于求成通晓，又必须深入研读《肘后备急方》、《千金要方》及《千金翼方》、《外台秘要》这四书，斟酌《本事方》、《百证歌》、《九十论》、《明理论》等学说，相互参考试验考订，以慢慢等待领悟，这大概会有另一番境界了。大抵医生对于伤寒的研究，其致力往往在杂病未深入研究之前，其心得反而在杂病完全通晓之后，不亲身经历的人是不会知道的。追溯源头，事情不过如此；神妙通达，全在于个人。至于《圣济总录》、《太平惠民和剂局方》以下的书籍，则是学成之后阅读的，也足以开阔聪明才智并锻炼见识能力，不必一概排斥以自我局限。
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.