凡学医，必识五科七事。五科者，脉病证治，及其所因；七事者，所因复分为三。故因
脉以识病，因病以辨证，随证以施治，则能事毕矣。故《经》曰∶有是脉而无是诊者，非也
。究明三因，内外不滥，参同脉证，尽善尽美。
凡学脉，须先识七表八里九道名体证状，了然分别，然后以关前一分应动相类，分别内
外及不内外。又须知二十四脉，以四脉为宗，所谓浮沉迟数，分风寒暑湿，虚实冷热，交结
诸脉，随部说证，不亦乎。
凡审病，须先识名，所谓中伤寒暑风湿瘟疫时气，皆外所因；脏腑虚实，五劳六极，皆
内所因；其如金疮 折，虎野狼毒虫，涉不内外。更有三因备具，各有其名，所谓名不正
则言不顺，言不顺则事不成，学不可不备。
凡学审证，须知外病自经络入，随六经所出，井营输源经合各有穴道，起没流传，不可
不别。内病自五脏郁发，证候各有部分，溢出诸脉，各有去处。所谓上竟上，头项胸喉中事
也；下竟下，腹肚腰足中事也。
凡用药，须熟读本草，广看方书，雷公炮灸，随方过制，汗下补吐，轻重涩滑，燥润等
性，量病浅深，饮服多寡，五德五味，七情八反，升合分两，朝代不同，一一备学，将欲对
治，须识前后。故《经》曰∶先去新病，病当在后。
凡治病，先须识因，不知其因，病源无目。其因有三，曰内，曰外，曰不内外。内则七
情，外则六淫，不内不外，乃背经常，《金匮》之言，实为要道。《巢氏病源》，具列一千
八百余件，盖为示病名也，以此三条，病源都尽，不亦反约乎。
凡学医，既明五科，每科须识其要。脉有浮沉迟数，病有风劳气冷，证有虚实寒热，治
有汗下补吐，若于三因推明，外曰寒热风湿，内曰喜怒忧思，不内外曰劳逸作强，各有证候
，详而推之，若网在纲，有条不紊。
凡看古方类例，最是朝代沿革。升合分两差殊，若数味皆用分两，不足较也，第中间有
用升合枚数，大段不同。升斗秤尺，本自积黍，黍自不可见，度量衡卒亦难明。今以《钱谱
》推测，粗知梗概。
凡度者，分寸尺丈引。本以一黍之广为分，十分为寸，十寸为尺，十尺为丈，十丈为引
。观今之尺数等不同，如周尺长八尺，京尺长一尺六寸，淮尺长一尺二寸，乐尺长一尺二寸
五分，并以小尺为率，小尺既自三微起，却自可准。唐武德年，铸开元钱八分，当十二钱半
得一尺，排钱比之，十一个已及一尺，又不知唐用何尺。顾汉唐龠量，并用尺寸分布，尺寸
如是不齐，将何凭据，博古君子，必有说矣。
凡量者，龠合升斗斛。本以黄钟龠容十二铢，合龠为合，重二十四铢。今以钱准，则六
铢钱四个，比开元钱三个重，升斗斛皆累而成数。汉唐同用，至宋绍兴，升容千二百铢，则
古文六铢钱二百个，开元二百二十个，以绍兴一升得汉五升，其余私有，不足计也。
凡衡者，铢两斤钧石。亦以黄钟龠所容重十二铢，两之为两，二十四铢为两，十六两为
斤，三十斤为钧，四钧为石。每两则古文六铢钱四个、开元钱三个。至宋广秤，以开元钱十
个为两，今之三两，得汉唐十两明矣。《千金》《本草》，皆以古三两为今一两，以古三升
为今一升，诸药类例，尤为难辨。且如半夏一升准五两，不知用何升何两。此修合制度之要
务，不可不知。汉铜钱质如周钱，文曰半两，重如其文。孝文五年，钱益多而轻，乃更铸四
铢，其文为半两，杂以铅铁锡，非淆杂为巧，则不得赢，而奸或盗，磨钱质取熔。有司言
钱轻重，请郡国铸五铢钱，周郭有质，令不得磨取熔。则知汉以二半两钱为两，重十铢明矣
，汉唐例以二十四铢为一两，抑未知修史人改作唐例，亦不可知。观《钱谱》汉无六铢钱，
至唐方有，今以五铢钱十六个，正得开元钱十个重。又以六铢钱十二个，正得开元钱九个重
。则知开元钱每个以重八铢。唐武德四年铸开元通宝，径八分，重二铢四累，积十钱为两，
似难考据，明食货者，必有说焉。
按药书，汉方汤液，大剂三十余两，小剂十有余两，用水六升或七升，多煎取二升三升
，并分三服。若以古龠量水七升，煎今之三十两，未淹得过；况散末药只服方寸刀圭匕，丸
子如梧桐子大，极至三十粒，汤液岂得如此悬绝。又如风引汤，一剂计五十五两，每两只用
三指撮，水三升，煮三沸，去滓温服一升。观其煮制，每只三指撮，未应料剂如此之多，此
又可疑也。今以臆说，汉方当用半两钱二枚为一两，且以术附汤方较，若用汉两计一百八十
铢，得开元钱二十二个半重，若分三服，已是今之七钱半重一服；若以唐方准计，三百三十
六铢，得开元钱四十二个重，每服计今之十四钱重，大略可知；若以开元钱准得一百单五个
重，分三服，每服计三十五钱重。此犹是小剂，况有大剂各件，两数之多者，未易概举。留
心此道，幸少详焉。
凡古书所诠，不出脉病证治四科，而撰述家有不知此，多致显晦，文义重复。要当以四
字类明之，四字者，即名体性用也。如脉，浮则为名，举有余按不足为体，为风为虚曰性，
可补可汗曰用；如病，太阳伤风为名，感已啬啬为体，恶风自汗为性，传变经络为用；如证
，太阳风证为名，头项疼腰脚痛为体，不与诸经滥为性，候其进退为用；如治，药桂则为名
，出处形色为体，德味备缺为性，汗下补吐为用。以此推之，读《脉经》，看病源，推方证
，节本草，皆用此法，无余蕴矣。
凡是学习医学，必须认识五科七事。五科，指的是脉、病、证、治，以及它们产生的原因；七事，是指所因又细分为三类。所以通过脉象来识别疾病，通过疾病来辨别证候，根据证候来实施治疗，那么医术的要点就完备了。所以《内经》说：只有脉象而没有相应的诊察表现，是不对的。彻底弄清三因，内外病因不混淆，参合脉象与证候，才能尽善尽美。
凡是学习脉诊，必须先认识七表、八里、九道这十九种脉的名称、形态和证状，清楚地加以区分，然后用关前一分（寸部）来对应动相类似的脉象，分别判断是内因、外因还是不内外因。还需要了解二十四种脉象，以浮、沉、迟、数四种脉为根本，以此分辨风寒暑湿，虚实冷热，交错结合各种脉象，随着脉位来说明证候，不是很恰当吗？
凡是审查疾病，必须先认识病名，所谓中伤寒、暑、风、湿、瘟疫、时气，都属于外因；脏腑的虚实证候，五劳六极，都属于内因；至于金创骨折，虎狼毒虫咬伤，属于不内外因。更有三因具备的情况，各有其名称，所谓名分不正则言语不顺，言语不顺则事情办不成，学习不可不准备充分。
凡是学习审察证候，必须知道外感病邪从经络侵入，随着六经传变而出，井、荥、输、原、经、合各穴道，起止流传，不可不辨别。内伤病由五脏郁结发作，证候各有部位，溢出到各条经脉，各有去处。所谓“上竟上”，指头项胸喉中的事务；“下竟下”，指腹肚腰足中的事务。
凡是使用药物，必须熟读《本草》，广泛阅读方书，了解雷公炮制灸法，随方剂进行炮制，汗法、下法、补法、吐法，轻重涩滑，燥润等药性，衡量疾病的深浅，决定服用多少，五德五味，七情八反，升合分两，朝代不同，都要一一备学，将要对症施治，必须识得先后次序。所以《内经》说：先去新病，旧病自然在后（意指先治新感之病）。
凡是治病，必须先认识病因，不知道病因，病的源头就无法看清。病因有三类，叫内因、外因、不内外因。内因则是七情，外因则是六淫，不内不外，违背常理，《金匮要略》的话，实在是重要的道理。《巢氏病源》，详细列出了一千八百多种病症，大概是用来展示病名的，用这三条原则，病的源头都穷尽了，不是返璞归真吗？
凡是学习医学，既然明白了五科，每一科都必须认识其要点。脉有浮沉迟数，病有风劳气冷，证有虚实寒热，治有汗下补吐，如果在三因上推究明白，外因曰寒热风湿，内因曰喜怒忧思，不内外因曰劳逸作强，各有证候，详细推究，就像网在纲上一样，有条不紊。
凡是查看古方类别体例，最重要的是朝代的沿革。升合分两差异很大，如果几味药都用分两计算，还不足以比较，只是中间有用升合枚数的，差别非常大。升斗秤尺，原本积累黍米而成，黍米本身已不可见，度量衡最终也难以弄明白。现在依据《钱谱》推测，粗略知晓梗概。
凡度量的单位，是分、寸、尺、丈、引。本以一颗黍米的宽度作为一分，十分为一寸，十寸为一尺，十尺为一丈，十丈为一引。观察现在的尺数各不相同，如周尺长八尺（注：此处原文可能有误或特指某种比例，通常周尺较短，但依文直译），京尺长一尺六寸，淮尺长一尺二寸，乐尺长一尺二寸五分，都以小尺为标准，小尺既然从三微开始，就可以作为准则。唐武德年间，铸造开元钱直径八分，当十二个半钱得一尺，排列钱币比较，十一个已达到一尺，又不知唐代使用的是什么尺。看汉唐的龠量，都用尺寸分布，尺寸如果不齐，将凭借什么依据，博古君子，一定有说法。
凡量的单位，是龠、合、升、斗、斛。本以黄钟龠容纳十二铢，合龠为一合，重二十四铢。现在用钱来折算，六个铢重的钱四个，比开元钱三个重，升斗斛都是累加成数。汉唐通用，到了宋代绍兴年间，一升容纳一千二百铢，那么古文六铢钱两百个，开元通宝两百二十个，以绍兴一升相当于汉代五升，其余私有的，不计入统计。
凡衡的单位，是铢、两、斤、钧、石。也以黄钟龠所容纳的重量十二铢为基础，两倍为一两，二十四铢为一两，十六两为一斤，三十斤为一钧，四钧为一石。每两则相当于古文六铢钱四个、开元钱三个。到了宋代广秤，以开元钱十个为一两，现在的三两，相当于汉代唐代的十两，这是很明显的。《千金方》《本草》，都以古三两当作今一两，以古三升当作今一升，各类药物的例子，尤其难以辨别。比如半夏一升准五两，不知道用的是何升何两。这是修合制度的重要事务，不可不知道。汉代铜钱质地像周钱，文字曰半两，重量如其文字。孝文五年，钱增多而轻，于是重新铸造四铢钱，文字仍为半两，掺杂铅铁锡，不是为了巧诈混杂，否则无法获利，而奸民或许会偷盗，磨取钱质熔化。有关部门说钱轻重不一，请郡国铸造五铢钱，边缘有廓，令不得磨取熔化。则知汉代以两个半两钱为一两，重十铢，这是明确的。汉唐惯例以二十四铢为一两，或许未知修史人改为唐例，也不可得知。看《钱谱》汉代没有六铢钱，到了唐代才有，现在以五铢钱十六个，正好得到开元钱十个重。又以六铢钱十二个，正好得到开元钱九个重。则知开元钱每个重八铢。唐武德四年铸造开元通宝，直径八分，重二铢四累，累积十个钱为一两，似乎难以考证，精通经济史的人，一定有说法。
按药书记载，汉代方剂汤液，大剂三十多两，小剂十多两，用水六升或七升，多煎取二升三升，并分三次服用。如果用古龠量水七升，煎煮现在的三十两药，恐怕浸没过不了；何况散末药只服方寸刀圭匕，丸子如梧桐子大，极至三十粒，汤液岂能如此悬殊。又如风引汤，一剂计五十五两，每次只用三指撮，水三升，煮三沸，去渣温服一升。看其煮制方法，每次三指撮，不应料剂如此之多，这又可疑了。现在凭主观推测，汉代方剂应当用半两钱二枚为一两，且以术附汤方比较，如果用汉代两计算一百八十铢，得到开元钱二十二个半重，若分三次服用，已是现在的七钱半重一次；如果用唐代方剂标准计算，三百三十六铢，得到开元钱四十二个重，每次服用计现在的十四钱重，大致可以知晓；如果用开元钱折算得到一百零五个重，分三次服用，每次服用计三十五钱重。这还是小剂，况有大剂各件，两数多的，不容易一概列举。留心此道，希望稍微详细一点。
凡是古书所阐述的内容，不出脉、病、证、治四科，而撰写文章的人不知道这一点，多导致显晦不明，文义重复。应当以四个字分类阐明，这四个字，就是名、体、性、用。比如脉，浮就是名，举之有余按之不足就是体，为风为虚就是性，可补可汗就是用；比如病，太阳伤风为名，感到啬啬恶寒为体，恶风自汗为性，传变经络为用；比如证，太阳风证为名，头项疼腰脚痛为体，不与诸经混淆为性，观察其进退为用；比如治，药桂就是名，出处形色为体，德味备缺为性，汗下补吐为用。以此类推，读《脉经》，看病源，推方证，节本草，都用这种方法，就没有遗漏了。
In learning medicine, one must understand the Five Categories and Seven Matters. The Five Categories refer to pulse (Mai), disease (Bing), syndrome (Zheng), treatment (Zhi), and their causes; the Seven Matters indicate that the causes are further divided into three types. Therefore, by identifying diseases through pulses, distinguishing syndromes through diseases, and applying treatments according to syndromes, the essentials of medical practice are completed. Thus, the *Classic* states: having a specific pulse without corresponding diagnostic manifestations is incorrect. Thoroughly investigating the Three Causes ensures that internal and external factors are not confused, and integrating pulse and syndrome leads to perfection.
When learning pulse diagnosis, one must first recognize the names, forms, and manifestations of the Seventy-Nine Pulses (Seven Superficial, Eight Interior, Nine Miscellaneous), clearly distinguishing them. Then, using the cun position (distal part of the wrist) to correspond to similar dynamic phases, differentiate between internal, external, and neither-internal-nor-external causes. One must also understand the Twenty-Four Pulses, taking Floating (Fu), Deep (Chen), Slow (Chi), and Rapid (Shu) as the root, to distinguish Wind-Cold, Summer-Heat-Dampness, Deficiency-Excess, Cold-Heat, and various combined pulses, explaining syndromes according to pulse positions, which is appropriate.
When examining diseases, one must first know the disease names. Conditions such as contracting Cold, Summer-Heat, Wind, Dampness, Plague, or Seasonal Qi belong to External Causes; Zang-Fu Deficiency-Excess syndromes, Wu Lao (Five Exhaustions), and Liu Ji (Six Extremities) belong to Internal Causes; while injuries from metal weapons or fractures, bites from tigers, wolves, or poisonous insects belong to Neither-Internal-Nor-External Causes. There are cases where all Three Causes are present, each with its own name. As stated, if the name is not correct, speech will not be smooth; if speech is not smooth, affairs cannot be accomplished. Learning must be thoroughly prepared.
When learning to examine syndromes, one must know that external pathogens enter via the Meridians and spread according to the Six Channels (Liu Jing). The Jing-River, Ying-Spring, Shu-Stream, Yuan-Source, Jing-River, and He-Sea acupoints have specific origins, endings, and flows, which must be distinguished. Internal diseases arise from the stagnation and eruption of the Five Zang organs, with syndromes having specific locations and overflowing into various meridians. "Upper reaches the upper" refers to matters of the head, neck, chest, and throat; "lower reaches the lower" refers to matters of the abdomen, waist, and feet.
When using herbs, one must be familiar with the *Materia Medica* (Ben Cao) and widely read formula books, understanding Lei Gong's processing and moxibustion methods, and following prescription-specific preparations. One must master sweating, purging, tonifying, and emetic methods, as well as properties like heavy/light, astringent/slipping, drying/moistening. Dosage should be measured according to the depth of the disease, and the quantity of intake determined. The Five Virtues and Five Flavors, Seven Emotions and Eight Incompatibilities, and units of measurement (sheng, he, fen, liang) vary by dynasty and must be studied individually. When treating, one must know the sequence. Thus, the *Classic* says: eliminate new diseases first, and old diseases will follow.
In treating diseases, one must first identify the cause. Without knowing the cause, the source of the disease remains unclear. The causes are three: Internal, External, and Neither-Internal-Nor-External. Internal causes are the Seven Emotions; External causes are the Six Evils. Neither-internal-nor-external causes deviate from normal patterns. The words in the *Jin Gui Yao Lue* (Essential Prescriptions of the Golden Cabinet) represent a crucial principle. The *Chao Shi Bing Yuan* (Source of Diseases) lists over 1,800 conditions, primarily to display disease names. Using these three categories, the sources of all diseases are encompassed, achieving simplicity and comprehensiveness.
Having understood the Five Categories, one must grasp the essentials of each. Pulses include Floating, Deep, Slow, Rapid; diseases include Wind, Asthenia, Qi stagnation, Cold; syndromes include Deficiency-Excess, Cold-Heat; treatments include sweating, purging, tonifying, emesis. By clarifying the Three Causes—External (Cold, Heat, Wind, Dampness), Internal (Joy, Anger, Worry, Thought), and Neither-Internal-Nor-External (Labor, Rest, Exertion)—and detailing their syndromes, one can proceed systematically, like a net with its main rope.
When studying ancient formulas, the evolution of dynasties is paramount. Units of volume and weight differ significantly. If only weights are used for comparison, it is insufficient; differences in volume units (sheng, he) and counts (pieces) are substantial. Measures of length (sheng, dou, cheng, chi) were originally based on millet grains, which are no longer visible, making precise calibration difficult. Current estimates rely on the *Qian Pu* (Record of Coins) for an approximate understanding.
Length measures include fen, cun, chi, zhang, yin. One fen was originally the width of a single millet grain; ten fen make one cun; ten cun make one chi; ten chi make one zhang; ten zhang make one yin. Modern chi lengths vary: Zhou chi was eight chi long (note: text implies relative scale), Beijing chi is 1.6 chi, Huai chi is 1.2 chi, and Music chi is 1.25 chi. Taking the smaller chi as the standard, starting from three wei, provides a reference. In the Wude era of Tang, Kaiyuan Tongbao coins were cast with a diameter of 0.8 fen; twelve and a half coins equaled one chi. Comparing coins, eleven reached one chi, but the specific chi used in Tang remains unknown. Han and Tang volumes used chi distributions; inconsistencies in chi suggest reliance on other evidence, likely explained by antiquarians.
Volume measures include Yue, He, Sheng, Dou, Hu. Originally, a Huangzhong Yue held twelve zhu; two Yue made one He, weighing twenty-four zhu. Using coins as a standard, four six-zhu coins weighed more than three Kaiyuan coins. Sheng, Dou, and Hu were cumulative. Han and Tang shared standards, but in Song Xingdao era, one sheng held 1,200 zhu. Thus, 200 ancient six-zhu coins or 220 Kaiyuan coins equaled one Xingdao sheng, equivalent to five Han sheng. Private variations are negligible.
Weight measures include zhu, liang, jin, jun, shi. Based on the weight of a Huangzhong Yue (12 zhu), two times this amount is one liang (24 zhu); sixteen liang make one jin; thirty jin make one jun; four jun make one shi. Each liang equaled four ancient six-zhu coins or three Kaiyuan coins. In Song Guangcheng, ten Kaiyuan coins equaled one liang; thus, three modern liang equal ten Han/Tang liang. *Qian Jin Fang* and *Ben Cao* treat ancient three liang as modern one liang, and ancient three sheng as modern one sheng, making drug classification difficult. For example, Ban Xia (Pinelliae Rhizoma) one sheng equals five liang, but which sheng and liang? This is crucial for compounding regulations. Han copper coins resembled Zhou coins, inscribed "Ban Liang," weighing as inscribed. In the fifth year of Emperor Wen, coins became lighter, so Si Zhu coins were cast, still inscribed "Ban Liang," mixed with lead, iron, tin to prevent counterfeiting. Officials requested Wu Zhu coins with edges to prevent shaving. Thus, Han used two Ban Liang coins as one liang, weighing ten zhu. Han/Tang conventionally used 24 zhu per liang, though historians may have altered this. *Qian Pu* shows no six-zhu coins in Han, appearing only in Tang. Sixteen Wu Zhu coins equal ten Kaiyuan coins in weight; twelve six-zhu coins equal nine Kaiyuan coins. Thus, one Kaiyuan coin weighs eight zhu. Kaiyuan Tongbao, cast in Wude 4th year, diameter 0.8 fen, weight 2 zhu 4 lei, ten coins make one liang. This is hard to verify, but experts in economic history have explanations.
According to herbal texts, Han decoctions used large doses of over 30 liang, small doses over 10 liang, boiled in 6-7 sheng of water down to 2-3 sheng, taken in three doses. Boiling 30 liang of herbs in 7 sheng of ancient water might not suffice. Powdered medicines were taken in measure of fang cun dao gui bi, pills sized like paulownia seeds, max 30 pills. Decoctions shouldn't vary so drastically. For example, Feng Yin Tang used 55 liang per dose, taken as three fingers' pinch, boiled in 3 sheng water for three boils, strained, warm drink 1 sheng. The dosage seems excessive for such preparation. Subjectively, Han formulas likely used two Ban Liang coins as one liang. Comparing with Zhu Fu Tang: Han 180 zhu equals 22.5 Kaiyuan coins; divided by three doses, 7.5 modern qian per dose. Tang standard 336 zhu equals 42 Kaiyuan coins; 14 modern qian per dose. Using Kaiyuan standard 105 zhu, divided by three, 35 qian per dose. Even small doses vary greatly; large doses are harder to generalize. Careful study is recommended.
Ancient texts cover Pulse, Disease, Syndrome, Treatment. Authors often ignore this, causing confusion and repetition. Classify using Four Characters: Name (Ming), Substance/Form (Ti), Nature/Property (Xing), Function/Application (Yong). E.g., Pulse: Floating is Name; abundant on pressure, deficient on release is Form; Wind/Deficiency is Nature; Tonify/Sweat is Function. Disease: Taiyang Wind Strike is Name; Chills are Form; Fear of wind/sweating is Nature; Meridian transmission is Function. Syndrome: Taiyang Wind Syndrome is Name; Head/neck/waist pain is Form; Distinct from other meridians is Nature; Monitoring progression is Function. Treatment: Gui Zhi (Cinnamon Twig) is Name; Origin/color/form is Form; Flavor/virtue is Nature; Sweat/Purge/Tonify/Emesis is Function. Applying this to reading *Mai Jing*, *Bing Yuan*, formulas, and *Ben Cao* leaves nothing unexplained.