然后引动伏邪，内应外合，成为大病，有极轻微的病，愈治愈重，就使延来名手，也不能够一扫而空，都是关涉着伏邪。就为伏邪病治法，既不能发表，又不能攻里，须要安心定志，慢慢把病邪引出，见景生情，因症立方，否则有力没处使，英雄无用武之地，倘用霸药，立见变端。
从前扁鹊见齐桓侯，望色而请治，桓侯病的就是伏邪症。仲景见王仲宣。望色而与药，仲宣病的也是伏邪症。桓侯、仲宣，不听而死，史册所载，非虚语也。
人身之六经六经是什么东西？
经就是经脉，人身上的脉，有纵有横，横的叫做络脉，纵的叫做经脉，那经脉共有六条，三条是阳经，三条是阴经，三阴三阳，就是六经。
六经各有名目，三阳经，一是太阳，二是阳明，三是少阳；三阴经，一是太阴，二是少阴，三是厥阴。六经的病症，各各不同，治法也各各不同，并且讲到六经的病症，不运是经脉为病，还有经气为病，那经气比了经脉还要重要。
从前柯韵伯讲六经经气，最为透切，他把周朝地理来譬解，他说六经犹之周朝的列国，腰以上为三阳经地面，三阳主外，而本乎里，里边的心就是三阳经气夹界的地方，内由心胸，外自巅顶，前至额颅，后至肩背，下及于足，内含膀胱，都是太阳地面，这一经统领荣卫，主一身之表症，犹之近边御敌之国。
内自心胸，至胃及肠，外自额颅，由面至腹，下及于足，都是阳明地面，这一经多气多血，统领一身的肌肉。
由心至咽，出口颊，上耳目，斜至巅，外自胁，内属胆。都是少阳地面，统领一身之腠理，外邻太阳，内近阳明。犹之京畿地方。
腰以下是三阴地面，三阴经主里不及外，愎部就是三阴经夹界的地方，从大腹由脾及二腹魄门，为太阴地面。从腹内到两臂，及膀胱溺道，为少阴地面。自腹内由肝上膈至心，从胁肋下及小愎宗筋。为厥阴地面，这厥阴一经，通行三焦，主一身之里症，犹之周京夹铺之国。
太阴阳明，同居异治，犹之周公召公分陕的故事，少阴、太阳、厥阴、少阳四经的部位，有内外、出入、上下牵引之不同，犹之周天子分土域民，犬牙相错的制度，所以六经之经气，犹之列国之地面，六经之经脉，犹之周家之道路。
六经之病，有正邪、客邪、合病、并病、属脾、属胃者，犹之寇贼充斥，或在本境，或在邻国，或入京师。太阳经经气，地面最大，内邻少阴，外邻阳明。故病都有相关者，如小便不利，原是膀胱为病，偏偏少阴病里头，也有小便不利症，那是邪已及到太阳地界了。
腰痛本来是肾病，偏偏太阳病也有腰痛症，那是邪已到了步阴的地界了。
六七日不大便，明明是阳明症，偏偏兼有头痛身热，那是阳明热邪已经侵及太阳地界了。头项强痛，明明是太阳病，偏偏兼有鼻鸣、干呕，那是太阳风邪，已经侵着阳明地界了。
心胸的部位，明明是阳明地面。偏偏又是太阳的通衢大道，就为太阳主营卫，心胸确是营卫的本根，营与卫环周不休，犹之边邑下的吏民士卒，会于京畿，往来不绝。即如喘而胸满这一症，确是太阳外邪进了阳明地面，大大的骚扰，所以称它为太阳阳明合病。倘使头不痛，项不强，胸中痞硬，气冲咽喉，不得息，那不是邪从太阳来，实是阳明实邪结于胸中，犹之乱民骚聚本境而为患。
心为六经之主，所以六经都有心烦症，倘使没有头项强痛，那么这个烦不属太阳，没有往来寒热，那么这个烦不属少阳，没有见三阴症，那么这个烦不属三阴了，所以心愦愦，心怵惕，心懊忄农，一切的虚烦，都属阳明，为的是心就住在阳明的地位。
阳明差不多就是京师，所以心呀腹呀，都在那里，邪在心。症见虚烦，邪在腹，症见实热，就为心在上为阳，属于无形；腹在下为阴，属于有形。人身上的病动与心腹相关，阳邪聚在心里头，阴邪聚在腹里头，肝为阴中之阳。故能使阴邪上搏于心，阳明主在里之阳，故能使阳邪下聚于腹。
再以兵法来譬喻，用兵之要，在明地形，必先明乎六经之路，才知贼寇所从来，知道某方是某府的来路，某方是某部的去路。来路是边关，三阳经就是来路，是外境，三阴经就是[去路，是内域。]六经的来路，各各不同，太阳是条大路，少阳是条僻路，阳明是条直路，那太阴是近路。少阴是后路，厥阴是斜路。客邪多从三阳来，正邪多由三阴起，犹之外寇从边关至，乱民自内地生。
明六经的地形，始得握百病之枢机，详六经的来路，乃得操治病之规则，以症来论，伤寒是大寇，病从外来；中风是流寇，病因旁及；杂病是乱民，病由中起，所以治病之法，第一须认明是何等之寇，第二须认明由何地而起。
发于其境，便御之本境，移祸邻郡，即两路夹攻，如邪入太阳地面，即汗而散之，犹之敌军陈利兵于要害，乘其未定而击之也；邪之轻者在卫分，重者在营分，尤重者在胸瞩，犹之寇浅者在关外，其深者在关上，尤深者在关内也，所以麻黄汤为关外之师，桂枝汤、葛根汤为关上之师，大青龙汤、小青龙汤为关内之师矣。
人身之六经，有六经之经脉，六经之经气，病袭吾身，即犯经气，中医对于仲景《伤寒论》毕世穷研-并不是研究伤寒一症，实是研究六经经气，以认明经气，对付百病，便不致如云中捉月，雾里看花矣，医者固不可不知，非医者亦不可不知。
人身之体用我的六经话儿，才在《医林》上刊出，就有人来问我，你们中医的学说，总是令人不可捉摸，气呀血呀营呀卫呀，说得很闹忙，老实说，只有血大家还看得见，其余卫呀营呀气呀，不过你们姑妄言之，我们姑妄听之而已。现在你把六经讲得天花乱坠，一回几经络，一回儿经气，又是什么京畿咧列国咧，大路咧，直路咧，斜路咧，后路咧，五花八门，闹得人家头晕脑胀，究竟怎么一回事，你且说一个明白。我回他，你这一番话，未免用西医的主观来观测我们中医了，根本上就大大错误。
要晓得人身上有两个部分，一个是体的部分，一个是用的部分，什么叫做体，体就是形体，什么叫做用，用就是作用。凡是在外的头面、身子、五官、四肢，在里的五脏、六腑以及皮肤、毛发、肌肉、腠理、筋骨，一切目力所能视的，都是体的部分，那四肢百骸之所以动作，脏腑气血之所以运行，脏腑十二官，手足十二经。凡精神之所寄，魂魄之所藏，气血之所行，意志之所出，都与十二官十二经有极大关系。一切目力所视不到的，而于此身为发号施令之总司令，都是用的部分。
体的部分，西医最为注重。用的部分中医最为注重。西医对于人体解剖，一层层剖去，一处处解开，筋肉、皮骨、心、肺、胃、肠、眼球、耳膜、动脉、静脉，知之必审，说之必明，对于人体化验，分析之为原子细胞、白血球、赤血球、淋巴隙、抗毒素、淀粉质、盐质、铁质、磷质等等种种，而于精神、魂魄、意志、动作倒都不研究，视人体为机械，此是西医之所长，即是西医之所短。
用的部分，中医最为注重，中医深知用是活的，体是死的，人之所以为人，全恃着用的部分，倘使专究体的部分，那么把榘纣和尧舜同时解剖，恁你解剖得精，分析得细，尧舜何以如是之仁，桀纣何以如是之暴，断然分析不出。孟子说过，“然则犬之性。犹牛之性，牛之性犹人之性欤”?从体的部分上求知，也是如此，中医深知其故，所以专在用的部分上着手。
中医并非全不知体的部分，中医对于体的部分，毛发、皮肤、肌肉、腠理、筋骨、脉络、脏腑、气血、营卫，无不真知灼见，惟原子细胞、白血球、赤血球、铁质、磷质不谈民众医学论医之业为治病之工，非人人得而为之也，医之学为专门之学，非人人得而知之也，医理精深，病情万变，专攻其事者，精研极究，犹不能尽愈诸病，何况普通一般之民众。
然则民众医学何谓乎?日“吾所谓民众者，非精深之学理，乃浅近之治法耳，如砒鸩人人知其毒，参芪人人知其补，大黄芒硝人人知其寒，附子肉桂人人知其热，亦如是而已矣”。
徐灵胎有言，伤风则防风、荆芥；感寒则苏叶、葱头；咳嗽则苏子、杏仁；伤食则山楂、神曲：伤暑则香薷、广藿；疟疾则柴胡汤加减；痢疾则黄芩汤加减，此皆相传之定法，千古不能易也。
其言浅近易知，可称民众医学，余推其意而广之，伤风用防风、荆芥，果然是对症发药，绝无错误，但是其间还须细为分辨，辨出风热与风寒，风寒用防风、荆芥；风热用桑叶、薄荷。感寒之苏叶、葱头，亦须分出浅深，寒之浅者宜苏叶；寒之深者宜葱头。咳嗽须辩出个畅与不畅，咳而不畅，邪郁在肺，非开泄不可，宜用桔梗、浙贝；咳而畅者，顺气为宜，当用苏子、杏仁；风热袭肺而咳，宜桑叶、牛蒡。伤食宜辨出是肉食所伤，是谷食所伤，谷食所伤宜曲，肉食所伤宜楂。伤暑尤颁辨出暑热与暑湿，暑湿则用香薷、广藿；暑热则用竹叶、芦根。至于疟、痢两症，原因复杂，变化尤多，断非民众医学所能疗治，谚有云“不信阴阳，但听雷响；不信医药，但吃砒霜”。吾之所谓民众医学，亦如是而已矣。
五行学说新释五行学说，在中医自身，认为最昏闷最难解释的一件事，有几位心中很明白，口中说不出，倘使你强要他说时，便如算命先生口吻。说上一大堆毫不相关的话，弄得人家非常怀疑。
在普通一般人呢，认五行学说为最暗晦最深奥的一种学问，决非寻常知识所能认识，昕能知晓，把医学看做了佛学仙道。
照了前一说呢，道之所以不明，照了后一说呢，道之所以不行，既不能明又不能行，外来的人趁这个热，就拔队来攻，诬我们为玄说，诬我们为不识病，诬我们为不能治病，如簧的舌峰，如剑的笔峰，摇笔弄舌，天天在报纸上大放厥辞。摇惑人心，人心不免为之浮动。
金木水火土，叫做五行，心肝睥肺肾。叫做五脏，究竟人身之五脏，为什么必与五行相配，这是一个问题。金木水火土五行，何以必有相生，又何以必有相克，又是一个问题。
这心肝睥肺肾五脏，与金木水火土五行，何以有息息相关，又是一个问题。
五脏各有动作，各有消长，五脏的动作，叫做脏气，脏气有消有长，使不有以形容之，则何以知脏气之为消为长，所以金木水火土是脏气之代名词，而五行生克是脏气消长之代名词，言皆有据，事尽可征，绝无一辞半语是玄说，是虚话。
肺为什么属于金，我告知你，金在五行叫做从革。从革是以肃降为义的，讲到肺的脏气，原是以降下为治节，称肺为金，无非表示肺气肃降罢了，绝无别种神秘意义。
肝为什么属于木，我告知你，木在五行叫做曲直，曲直是以升泄为义的，直升叫做直，横泄叫做曲，讲到肝的脏气，原是以升泄为用，称肝为木，无非表示肝气升泄罢了，绝无别种神秘意义。
心为什么属于火，我告知你。火在五行叫做炎上，炎上就是动的意义，讲到心的脏气，原是以动为用的，称心为火，无非表示心气主动罢了，此外绝无神秘意义。
肾为什么属于水，我告知『尔，水在五行叫做润下，润下就是静的意义，讲到肾的脏气，原是以静为主的，称肾为水，无非表示肾气主静罢了，此外绝无神秘意义。
脾为什么属于土，我告知你，土在五行叫作稼穑，稼穑，就是和的意义，怎么叫做和？
悼一句文，和者和也，就是不升不降，不动不静，也可说得，亦升亦降，亦动亦静，我这一句话，未免有点子矛盾，既然不升不降，如何说亦升亦降，既然不动不静，如何说亦动亦静，其实真是不升不降，不动不静，那不成了个死体么，所以亦升亦降，亦动亦静几句补充的话，是不能少的，闲文少叙，言归正传，讲到脾的脏气，原是以和为主的，称脾为土，无非表示睥气主和罢了，此外绝无什么神秘。
讲到相生相克，更是容易，肺气既然肃降，肾气自不致于妄动，肾气不妄动就静了，这就是金生水。肾也既静，肝阴自然得养，肝阴得养，肝就得所了，这就是水生木。肝气升泄，那么心阳得了扶助，自然就要动作，这就是木生火。心动既剧，脾阳自然被着鼓动，睥阳被动，自然加倍的发越，这就是火生土。脾气既和，肺家肃降，自然没有阻滞，这就是土生金。那么所谓相生者，不过彼脏之气，帮助此一脏之气以相长是也。我现在敲开天窗说亮话，不卖葫芦中秘药，大家对于这五行，总该认识一点了。
再讲到相克的话，肺气肃降不已，就能够制肝气之升泄，这就是金克木。肝气升泄不已，就能够碍及脾气之和，这就是木克土。脾运过程，就能够耗及肾阴，这就是土克水。肾气过静，就能上制心气之浮动，这就是水克火。心气太动，就要碍及肺家之肃降，这就是火克金。那所谓相克者，不过此脏之气太胜。碍及彼一脏之动作，换句文话儿，就是相消也。相生相克，不过是脏气消长的代名词，长就是相生，消就是相克。
五行生克，在诊病上论，诊外感病是用不着的，所以仲景《伤寒论》没有一个字提到五行生克。诊治杂病，才用得着审查脏气，所以郎中非驳五行的，不曾认识五行真面目，遇着病证，辄以五行生克眩人的，也不曾认识五行真面目。
随后引动潜伏的病邪，内外相应，形成重病。有的病极其轻微，却越治越重，即使请来名医，也无法彻底治愈，这都是因为涉及伏邪的缘故。对于伏邪病的治疗，既不能发汗解表，也不能攻下里实，必须安心定志，慢慢将病邪引出。要见机行事，根据症状制定方剂，否则有力无处使，英雄无用武之地；如果滥用猛药，立刻会出现变证。
从前扁鹊见到齐桓侯，通过观察面色请求治疗，齐桓侯得的正是伏邪症。张仲景见到王仲宣，通过观察面色给予药物，王仲宣得的也是伏邪症。齐桓侯和王仲宣因不听劝告而死，史书所载，并非虚言。
人身有六经。六经是什么东西？
经脉就是经络，人身上的脉，有纵有横，横向的叫络脉，纵向的叫经脉。那经脉共有六条，三条是阳经，三条是阴经，三阴三阳，就是六经。
六经各有名称。三阳经，一是太阳（Taiyang），二是阳明（Yangming），三是少阳（Shaoyang）；三阴经，一是太阴（Taiyin），二是少阴（Shaoyin），三是厥阴（Jueyin）。六经的病症各不相同，治法也各不相同。并且讲到六经的病症，不仅仅是经脉为病，还有经气为病，那经气比经脉还要重要。
从前柯韵伯讲解六经经气，最为透彻。他用周朝的地理来比喻解释，他说六经就像周朝的列国。腰以上为三阳经的地面，三阳主外，但本源于里，里边的心是三阳经气交汇的地方。内由心胸，外自头顶，前至额头，后至肩背，下及于足，内含膀胱，都是太阳地面。这一经统领营卫（Nutritive and Defensive Qi），主一身之表症，就像邻近边境抵御外敌的国家。
内自心胸，至胃及肠，外自额头，由面至腹，下及于足，都是阳明地面。这一经多气多血，统领一身的肌肉。
由心至咽，出口颊，上耳目，斜至头顶，外自胁肋，内属胆。都是少阳地面，统领一身之腠理（Skin and hair pores），外邻太阳，内近阳明。就像京畿地区。
腰以下是三阴地面。三阴经主里不及外，腹部就是三阴经交汇的地方。从大腹由脾及二便之门，为太阴地面。从腹内到两臂，及膀胱尿道，为少阴地面。自腹内由肝上膈至心，从胁肋下及小腹宗筋，为厥阴地面。这厥阴一经，通行三焦（Sanjiao/Triple Burner），主一身之里症，就像周朝京城附近的辅佐之国。
太阴和阳明，同居异治，就像周公和召公分陕而治的故事。少阴、太阳、厥阴、少阳四经的部位，有内外、出入、上下牵引的不同，就像周天子分封土地百姓，犬牙交错的制度。所以六经的经气，就像列国的地面；六经的经脉，就像周家的道路。
六经的病，有正邪、客邪、合病（Combined Disease）、并病（Concurrent Disease）、属脾、属胃者，就像寇贼充斥，或在本境，或在邻国，或进入京师。太阳经经气，地面最大，内邻少阴，外邻阳明。所以病都有相关者。如小便不利，原是膀胱为病，偏偏少阴病里头，也有小便不利症，那是邪已到了太阳地界了。
腰痛本来是肾病，偏偏太阳病也有腰痛症，那是邪已到了太阳的地界了。
六七日不大便，明明是阳明症，偏偏兼有头痛身热，那是阳明热邪已经侵及太阳地界了。头项强痛，明明是太阳病，偏偏兼有鼻鸣、干呕，那是太阳风邪，已经侵着阳明地界了。
心胸的部位，明明是阳明地面。偏偏又是太阳的通衢大道，就为太阳主营卫，心胸确是营卫的本根，营与卫环周不休，就像边邑下的吏民士卒，会于京畿，往来不绝。即如喘而胸满这一症，确是太阳外邪进了阳明地面，大大的骚扰，所以称它为太阳阳明合病。倘使头不痛，项不强，胸中痞硬，气冲咽喉，不得息，那不是邪从太阳来，实是阳明实邪结于胸中，就像乱民骚聚本境而为患。
心为六经之主，所以六经都有心烦症。倘使没有头项强痛，那么这个烦不属太阳；没有往来寒热（Alternating chills and fever），那么这个烦不属少阳；没有见三阴症，那么这个烦不属三阴了。所以心愦愦（Confusion of heart），心怵惕（Fearfulness of heart），心懊憹（Restlessness of heart），一切的虚烦，都属阳明，为的是心就住在阳明的地位。
阳明差不多就是京师，所以心呀腹呀，都在那里。邪在心，症见虚烦；邪在腹，症见实热。就为心在上为阳，属于无形；腹在下为阴，属于有形。人身上的病动与心腹相关，阳邪聚在心里头，阴邪聚在腹里头。肝为阴中之阳，故能使阴邪上搏于心；阳明主在里之阳，故能使阳邪下聚于腹。
再以兵法来比喻，用兵的要领，在于明了地形，必须先明了六经的路径，才知道贼寇从哪里来，知道某方是某府的来路，某方是某部的去路。来路是边关，三阳经就是来路，是外境；三阴经就是去路，是内域。六经的来路，各不相同。太阳是条大路，少阳是条僻路，阳明是条直路，太阴是近路，少阴是后路，厥阴是斜路。客邪多从三阳来，正邪多由三阴起，就像外寇从边关至，乱民自内地生。
明了六经的地形，始得掌握百病的枢机；详查六经的来路，乃得操持治病的规则。以症来论，伤寒（Cold Damage）是大寇，病从外来；中风（Wind Strike）是流寇，病因旁及；杂病是乱民，病由中起。所以治病之法，第一须认明是何等之寇，第二须认明由何地而起。
发于其境，便御之本境；移祸邻郡，即两路夹攻。如邪入太阳地面，即汗而散之，就像敌军陈列利兵于要害，乘其未定而击之也；邪之轻者在卫分，重者在营分，尤重者在胸臆，就像寇浅者在关外，其深者在关上，尤深者在关内也。所以麻黄汤（Ephedra Decoction）为关外之师，桂枝汤（Cinnamon Twig Decoction）、葛根汤（Pueraria Decoction）为关上之师，大青龙汤（Major Green Dragon Decoction）、小青龙汤（Minor Green Dragon Decoction）为关内之师矣。
人身之六经，有六经之经脉，六经之经气。病袭吾身，即犯经气。中医对于仲景《伤寒论》毕世穷研，并不是研究伤寒一症，实是研究六经经气，以认明经气，对付百病，便不致如云中捉月，雾里看花矣。医者固不可不知，非医者亦不可不知。
人身之体用，我的六经话儿，才在《医林》上刊出，就有人来问我：“你们中医的学说，总是令人不可捉摸，气呀血呀营呀卫呀，说得很闹忙，老实说，只有血大家还看得见，其余卫呀营呀气呀，不过你们姑妄言之，我们姑妄听之而已。现在你把六经讲得天花乱坠，一回儿经络，一回儿经气，又是什么京畿咧列国咧，大路咧，直路咧，斜路咧，后路咧，五花八门，闹得人家头晕脑胀，究竟怎么一回事，你且说一个明白。”我回他：“你这一番话，未免用西医的主观来观测我们中医了，根本上就大大错误。”
要晓得人身上有两个部分，一个是体的部分，一个是用的部分。什么叫做体？体就是形体。什么叫做用？用就是作用。凡是在外的头面、身子、五官、四肢，在里的五脏、六腑以及皮肤、毛发、肌肉、腠理、筋骨，一切目力所能视的，都是体的部分。那四肢百骸之所以动作，脏腑气血之所以运行，脏腑十二官，手足十二经。凡精神之所寄，魂魄之所藏，气血之所行，意志之所出，都与十二官十二经有极大关系。一切目力所视不到的，而于此身为发号施令之总司令，都是用的部分。
体的部分，西医最为注重。用的部分中医最为注重。西医对于人体解剖，一层层剖去，一处处解开，筋肉、皮骨、心、肺、胃、肠、眼球、耳膜、动脉、静脉，知之必审，说之必明。对于人体化验，分析之为原子细胞、白血球、赤血球、淋巴隙、抗毒素、淀粉质、盐质、铁质、磷质等等种种，而于精神、魂魄、意志、动作倒都不研究，视人体为机械。此是西医之所长，即是西医之所短。
用的部分，中医最为注重。中医深知用是活的，体是死的。人之所以为人，全恃着用的部分。倘使专究体的部分，那么把桀纣和尧舜同时解剖，恁你解剖得精，分析得细，尧舜何以如是之仁，桀纣何以如是之暴，断然分析不出。孟子说过，“然则犬之性，犹牛之性，牛之性犹人之性欤？”从体的部分上求知，也是如此。中医深知其故，所以专在用的部分上着手。
中医并非全不知体的部分。中医对于体的部分，毛发、皮肤、肌肉、腠理、筋骨、脉络、脏腑、气血、营卫，无不真知灼见。惟原子细胞、白血球、赤血球、铁质、磷质不谈。民众医学论医之业为治病之工，非人人得而为之也；医之学为专门之学，非人人得而知之也。医理精深，病情万变，专攻其事者，精研极究，犹不能尽愈诸病，何况普通一般之民众。
然则民众医学何谓乎？曰：“吾所谓民众者，非精深之学理，乃浅近之治法耳。如砒鸩人人知其毒，参芪人人知其补，大黄芒硝人人知其寒，附子肉桂人人知其热，亦如是而已矣”。
徐灵胎有言：伤风则防风、荆芥；感寒则苏叶、葱头；咳嗽则苏子、杏仁；伤食则山楂、神曲；伤暑则香薷、广藿；疟疾则柴胡汤加减；痢疾则黄芩汤加减。此皆相传之定法，千古不能易也。
其言浅近易知，可称民众医学。余推其意而广之：伤风用防风、荆芥，果然是对症发药，绝无错误，但是其间还须细为分辨，辨出风热与风寒。风寒用防风、荆芥；风热用桑叶、薄荷。感寒之苏叶、葱头，亦须分出浅深。寒之浅者宜苏叶；寒之深者宜葱头。咳嗽须辩出个畅与不畅。咳而不畅，邪郁在肺，非开泄不可，宜用桔梗、浙贝；咳而畅者，顺气为宜，当用苏子、杏仁；风热袭肺而咳，宜桑叶、牛蒡。伤食宜辨出是肉食所伤，是谷食所伤。谷食所伤宜曲，肉食所伤宜楂。伤暑尤须辨出暑热与暑湿。暑湿则用香薷、广藿；暑热则用竹叶、芦根。至于疟、痢两症，原因复杂，变化尤多，断非民众医学所能疗治。谚有云“不信阴阳，但听雷响；不信医药，但吃砒霜”。吾之所谓民众医学，亦如是而已矣。
五行学说新释。五行学说，在中医自身，认为最昏闷最难解释的一件事。有几位心中很明白，口中说不出，倘使你强要他说时，便如算命先生口吻，说上一大堆毫不相关的话，弄得人家非常怀疑。
在普通一般人呢，认五行学说为最暗晦最深奥的一种学问，决非寻常知识所能认识、听闻知晓，把医学看做了佛学仙道。
照了前一说呢，道之所以不明；照了后一说呢，道之所以不行。既不能明又不能行，外来的人趁这个热，就拔队来攻，诬我们为玄说，诬我们为不识病，诬我们为不能治病。如簧的舌峰，如剑的笔峰，摇笔弄舌，天天在报纸上大放厥辞，摇惑人心，人心不免为之浮动。
金木水火土，叫做五行；心肝脾肺肾，叫做五脏。究竟人身之五脏，为什么必与五行相配，这是一个问题。金木水火土五行，何以必有相生，又何以必有相克，又是一个问题。这心肝脾肺肾五脏，与金木水火土五行，何以有息息相关，又是一个问题。
五脏各有动作，各有消长。五脏的动作，叫做脏气。脏气有消有长，使不有以形容之，则何以知脏气之为消为长？所以金木水火土是脏气之代名词，而五行生克是脏气消长之代名词。言皆有据，事尽可征，绝无一辞半语是玄说，是虚话。
肺为什么属于金？我告知你，金在五行叫做从革。从革是以肃降为义的。讲到肺的脏气，原是以降下为治节，称肺为金，无非表示肺气肃降罢了，绝无别种神秘意义。
肝为什么属于木？我告知你，木在五行叫做曲直。曲直是以升泄为义的。直升叫做直，横泄叫做曲。讲到肝的脏气，原是以升泄为用，称肝为木，无非表示肝气升泄罢了，绝无别种神秘意义。
心为什么属于火？我告知你，火在五行叫做炎上。炎上就是动的意义。讲到心的脏气，原是以动为用的，称心为火，无非表示心气主动罢了，此外绝无神秘意义。
肾为什么属于水？我告知你，水在五行叫做润下。润下就是静的意义。讲到肾的脏气，原是以静为主的，称肾为水，无非表示肾气主静罢了，此外绝无神秘意义。
脾为什么属于土？我告知你，土在五行叫作稼穑。稼穑，就是和的意义。怎么叫做和？悼一句文，和者和也，就是不升不降，不动不静，也可说得，亦升亦降，亦动亦静。我这一句话，未免有点子矛盾，既然不升不降，如何说亦升亦降？既然不动不静，如何说亦动亦静？其实真是不升不降，不动不静，那不成了个死体么？所以亦升亦降，亦动亦静几句补充的话，是不能少的。闲文少叙，言归正传。讲到脾的脏气，原是以和为主的，称脾为土，无非表示脾气主和罢了，此外绝无什么神秘。
讲到相生相克，更是容易。肺气既然肃降，肾气自不致于妄动，肾气不妄动就静了，这就是金生水。肾也既静，肝阴自然得养，肝阴得养，肝就得所了，这就是水生木。肝气升泄，那么心阳得了扶助，自然就要动作，这就是木生火。心动既剧，脾阳自然被着鼓动，脾阳被动，自然加倍的发越，这就是火生土。脾气既和，肺家肃降，自然没有阻滞，这就是土生金。那么所谓相生者，不过彼脏之气，帮助此一脏之气以相长是也。我现在敲开天窗说亮话，不卖葫芦中秘药，大家对于这五行，总该认识一点了。
再讲到相克的话。肺气肃降不已，就能够制肝气之升泄，这就是金克木。肝气升泄不已，就能够碍及脾气之和，这就是木克土。脾运过程，就能够耗及肾阴，这就是土克水。肾气过静，就能上制心气之浮动，这就是水克火。心气太动，就要碍及肺家之肃降，这就是火克金。那所谓相克者，不过此脏之气太胜，碍及彼一脏之动作。换句文话儿，就是相消也。相生相克，不过是脏气消长的代名词，长就是相生，消就是相克。
五行生克，在诊病上论，诊外感病是用不着的，所以仲景《伤寒论》没有一个字提到五行生克。诊治杂病，才用得着审查脏气。所以郎中非驳五行的，不曾认识五行真面目；遇着病证，辄以五行生克眩人的，也不曾认识五行真面目。
Subsequently, latent pathogens (latent pathogens) are triggered, responding internally and externally, forming severe diseases. Some diseases are extremely mild yet become heavier with treatment; even if renowned physicians are summoned, they cannot eradicate them completely. This is all related to latent pathogens. For the treatment of latent pathogen diseases, neither releasing the exterior through sweating nor purging the interior is appropriate. One must remain calm and composed, slowly drawing out the pathogens. One must adapt to circumstances and formulate prescriptions based on symptoms. Otherwise, strength will be wasted, like a hero without a battlefield. If harsh medicines are used arbitrarily, complications will arise immediately.
In the past, Bian Que saw Duke Huan of Qi and requested treatment by observing his complexion. Duke Huan suffered from a latent pathogen syndrome. Zhang Zhongjing saw Wang Zhongxuan and prescribed medicine by observing his complexion. Wang Zhongxuan also suffered from a latent pathogen syndrome. Both Duke Huan and Wang Zhongxuan died because they did not listen to advice, as recorded in historical texts, which is no falsehood.
The human body has six meridians (Six Meridians). What are the six meridians?
Meridians refer to the channels. The vessels in the human body run longitudinally and transversely. Those running transversely are called collateral vessels (Collateral Vessels), and those running longitudinally are called meridians. There are six main meridians: three yang meridians and three yin meridians. The three yins and three yangs constitute the six meridians.
Each of the six meridians has its own name. The three yang meridians are: one, Taiyang (Greater Yang); two, Yangming (Bright Yang); three, Shaoyang (Lesser Yang). The three yin meridians are: one, Taiyin (Greater Yin); two, Shaoyin (Lesser Yin); three, Jueyin (Terminal Yin). The symptoms of the six meridians differ from each other, and their treatments also differ. Furthermore, when discussing the symptoms of the six meridians, it is not merely about disease in the meridians themselves, but also about disease in the meridian qi (Meridian Qi). Meridian qi is more important than the physical meridians.
In the past, Ke Yunbo explained the meridian qi of the six meridians most thoroughly. He used the geography of the Zhou Dynasty as an analogy. He said that the six meridians are like the states of the Zhou Dynasty. The area above the waist belongs to the three yang meridians. The three yangs govern the exterior but originate from the interior. The heart inside is the junction where the qi of the three yang meridians converges. From the chest and heart internally, to the vertex externally, forward to the forehead, backward to the shoulders and back, down to the feet, and including the bladder, this is all the territory of the Taiyang meridian. This meridian controls Ying and Wei (Nutritive and Defensive Qi) and governs the exterior syndromes of the whole body, similar to a border state defending against enemies.
From the chest and heart internally to the stomach and intestines, from the forehead externally, across the face to the abdomen, and down to the feet, this is all the territory of the Yangming meridian. This meridian is rich in qi and blood and governs the muscles of the whole body.
From the heart to the throat, exiting at the cheeks, ascending to the ears and eyes, diagonally to the vertex, from the hypochondrium externally, and belonging to the gallbladder internally, this is all the territory of the Shaoyang meridian. This meridian governs the couli (skin and hair pores) of the whole body, adjacent to Taiyang externally and close to Yangming internally. It is like the capital region.
The area below the waist belongs to the three yin meridians. The three yins govern the interior rather than the exterior. The abdomen is the junction where the qi of the three yin meridians converges. From the great abdomen via the spleen to the orifices of defecation and urination, this is the territory of the Taiyin meridian. From within the abdomen to both arms, and to the bladder and urinary tract, this is the territory of the Shaoyin meridian. From within the abdomen via the liver up through the diaphragm to the heart, from the hypochondrium down to the lower abdomen and sinews, this is the territory of the Jueyin meridian. This Jueyin meridian circulates through the Sanjiao (Triple Burner) and governs the interior syndromes of the whole body, similar to states assisting the capital of Zhou.
Taiyin and Yangming reside in the same area but have different treatments, analogous to the story of the Duke of Zhou and the Duke of Shao dividing the realm. The positions of the Shaoyin, Taiyang, Jueyin, and Shaoyang meridians differ in terms of interior/exterior, entering/exiting, and upper/lower traction, analogous to the system of the Zhou Emperor distributing land and people with interlocking borders. Therefore, the meridian qi of the six meridians is like the territories of various states, and the meridians of the six meridians are like the roads of the Zhou family.
Diseases of the six meridians include direct pathogens, guest pathogens, combined diseases (Combined Disease), concurrent diseases (Concurrent Disease), and those belonging to the spleen or stomach. This is like bandits filling the land, either in their own territory, neighboring states, or entering the capital. The Taiyang meridian qi has the largest territory, adjacent to Shaoyin internally and Yangming externally. Thus, diseases are often related. For example, difficulty in urination is originally a disease of the bladder, yet in Shaoyin disease, there is also difficulty in urination. This indicates that the pathogen has reached the territory of Taiyang.
Lower back pain is originally a kidney disease, yet in Taiyang disease, there is also lower back pain. This indicates that the pathogen has reached the territory of Taiyang.
Constipation for six or seven days is clearly a Yangming syndrome, yet if accompanied by headache and fever, it indicates that Yangming heat pathogen has invaded the territory of Taiyang. Stiffness and pain in the head and neck is clearly a Taiyang disease, yet if accompanied by nasal congestion and dry retching, it indicates that Taiyang wind pathogen has invaded the territory of Yangming.
The chest and heart area is clearly the territory of Yangming. Yet it is also the thoroughfare of Taiyang. Because Taiyang governs Ying and Wei, the chest and heart are indeed the root of Ying and Wei. Ying and Wei circulate endlessly, like officials and soldiers in border towns gathering in the capital, coming and going continuously. For instance, panting and chest fullness is indeed due to external Taiyang pathogens entering the Yangming territory, causing significant disturbance. Hence, it is called a Combined Disease of Taiyang and Yangming. However, if there is no headache or neck stiffness, but rather chest oppression and hardness, with qi rushing to the throat preventing breathing, this is not a pathogen coming from Taiyang, but rather excess pathogen of Yangming knotting in the chest. This is like rebels gathering in their own territory to cause trouble.
The heart is the master of the six meridians, so all six meridians can present with heart vexation. If there is no stiffness and pain in the head and neck, this vexation does not belong to Taiyang. If there is no alternating chills and fever (Alternating chills and fever), this vexation does not belong to Shaoyang. If there are no signs of the three yin meridians, this vexation does not belong to the three yins. Therefore, heart confusion, heart fearfulness, and heart restlessness, along with all types of deficiency vexation, belong to Yangming, because the heart resides in the position of Yangming.
Yangming is almost like the capital, so the heart and abdomen are located there. When the pathogen is in the heart, symptoms show deficiency vexation; when the pathogen is in the abdomen, symptoms show excess heat. This is because the heart is superior and yang, belonging to the formless; the abdomen is inferior and yin, belonging to the formed. Diseases of the human body relate to the heart and abdomen. Yang pathogens gather in the heart, and yin pathogens gather in the abdomen. The liver is yang within yin, thus enabling yin pathogens to attack upward to the heart. Yangming governs interior yang, thus enabling yang pathogens to gather downward in the abdomen.
Using military strategy as an analogy again, the key to warfare is understanding terrain. One must first understand the paths of the six meridians to know where the enemy comes from, knowing which direction is the approach of a certain commandery and which is the retreat of a certain division. The approach is the border pass. The three yang meridians are the approach, the exterior realm. The three yin meridians are the retreat, the interior realm. The approaches of the six meridians are different. Taiyang is a major road, Shaoyang is a remote road, Yangming is a straight road, Taiyin is a shortcut, Shaoyin is a rear road, and Jueyin is a diagonal road. Guest pathogens mostly come from the three yang meridians, while direct pathogens mostly arise from the three yin meridians, just as foreign invaders come from border passes and rebels rise from the interior.
Understanding the terrain of the six meridians allows one to grasp the pivot of all diseases. Detailing the approaches of the six meridians allows one to control the rules of treatment. Discussing by symptoms, Cold Damage (Cold Damage) is a major invader, with disease coming from outside; Wind Strike (Wind Strike) is a roaming bandit, with disease spreading from the side; miscellaneous diseases are local rebels, with disease arising from within. Therefore, the method of treatment requires first identifying what kind of invader it is, and second, identifying where it originates.
If it arises in its own territory, defend it in that territory; if disaster shifts to a neighboring commandery, attack from two routes. If the pathogen enters the Taiyang territory, disperse it through sweating, just as attacking the enemy while they are deploying weapons at a strategic point before they are settled. Light pathogens are in the Wei level, heavy ones in the Ying level, and especially heavy ones in the chest. This is like shallow invaders outside the pass, deeper ones at the pass, and deepest ones inside the pass. Therefore, Mahuang Tang (Ephedra Decoction) is the army outside the pass, Guizhi Tang (Cinnamon Twig Decoction) and Gegen Tang (Pueraria Decoction) are the army at the pass, and Da Qinglong Tang (Major Green Dragon Decoction) and Xiao Qinglong Tang (Minor Green Dragon Decoction) are the army inside the pass.
The human body's six meridians have the meridians of the six meridians and the meridian qi of the six meridians. When disease attacks our body, it violates the meridian qi. TCM practitioners study Zhang Zhongjing's *Treatise on Cold Damage* (*Shanghan Lun*) throughout their lives not merely to study cold damage, but to study the meridian qi of the six meridians. By recognizing meridian qi to deal with all diseases, one will not be like trying to catch the moon in the clouds or looking at flowers in the fog. Physicians certainly must know this, and non-physicians should also know it.
My discussion on the substance and function of the human body using the six meridians was recently published in *Yi Lin*. Someone asked me: "Your TCM theories are always elusive. You talk about qi, blood, ying, and wei, making a big fuss. Honestly, only blood is visible to everyone else. As for wei, ying, and qi, you speak casually, and we listen casually. Now you explain the six meridians extravagantly, talking about meridians one moment and meridian qi the next, and mentioning capitals, states, major roads, straight roads, diagonal roads, and rear roads. It’s confusing and dizzying. What is it really? Explain it clearly." I replied: "Your words reflect a Western medical subjective perspective observing our TCM, which is fundamentally wrong."
One must understand that the human body has two parts: the part of substance (Ti) and the part of function (Yong). What is substance? Substance is the physical form. What is function? Function is the action. Everything visible to the eye, such as the head, face, body, five senses, limbs, internal five zang organs, six fu organs, skin, hair, muscles, couli, bones, and tendons, constitutes the part of substance. The movement of the four limbs and hundred joints, the circulation of zang-fu qi and blood, the twelve zang-officials, and the twelve hand-foot meridians. Where spirit resides, where hun and po are stored, where qi and blood flow, and where will emerges, all have a great relationship with the twelve officials and twelve meridians. Everything invisible to the eye, yet acting as the commander-in-chief issuing orders for this body, constitutes the part of function.
Western medicine focuses most on the part of substance. TCM focuses most on the part of function. Western medicine dissects the human body layer by layer, untangling everything. Muscles, skin, bones, heart, lungs, stomach, intestines, eyeballs, eardrums, arteries, and veins are studied meticulously and described clearly. In human testing, substances are analyzed into atoms, cells, white blood cells, red blood cells, lymph spaces, antitoxins, starch, salts, iron, phosphorus, etc., while spirit, hun, po, will, and movement are not studied. Viewing the human body as a machine is both the strength and the weakness of Western medicine.
TCM focuses most on the part of function. TCM deeply understands that function is alive and substance is dead. What makes a human a human relies entirely on the part of function. If one only studies the part of substance, then dissecting Jie and Zhou simultaneously, no matter how precise the dissection and analysis, one cannot determine why Yao and Shun were so benevolent and why Jie and Zhou were so tyrannical. Mencius said, "Then is the nature of dogs like the nature of cattle, and the nature of cattle like the nature of humans?" Seeking knowledge from the part of substance is likewise futile. TCM knows this well, so it focuses specifically on the part of function.
TCM is not completely ignorant of the part of substance. TCM has profound insight into the part of substance, including hair, skin, muscles, couli, bones, tendons, vessels, zang-fu organs, qi, blood, ying, and wei. However, it does not discuss atoms, cells, white blood cells, red blood cells, iron, or phosphorus. Folk medicine discusses medical practice as a craft of curing diseases, which is not something everyone can do. Medical learning is a specialized discipline, not something everyone can know. Medical principles are profound, and disease conditions change constantly. Even specialists who study intensively cannot cure all diseases, let alone ordinary people.
So what is folk medicine? I say: "What I mean by 'folk' is not profound theory, but simple treatment methods. Everyone knows arsenic and poison are toxic, ginseng and astragalus are tonifying, rhubarb and mirabilite are cold, and aconite and cinnamon are hot. It is just like that."
Xu Lingtai said: For wind-cold, use Fangfeng and Jingjie; for cold invasion, use Ziyeh and Congtou; for cough, use Suzi and Xingren; for food stagnation, use Shanzha and Shenqu; for summerheat, use Xiangru and Guanghuo; for malaria, modify Chaihu Tang (Bupleurum Decoction); for dysentery, modify Huangqin Tang (Scutellaria Decoction). These are traditional fixed methods, unchangeable for millennia.
His words are simple and easy to understand, worthy of being called folk medicine. I extend his meaning: Using Fangfeng and Jingjie for wind-cold is indeed symptomatic and error-free, but one must distinguish between wind-heat and wind-cold. For wind-cold, use Fangfeng and Jingjie; for wind-heat, use Sangye and Bohe. For cold invasion, Ziyeh and Congtou must also be distinguished by depth. For shallow cold, Ziyeh is suitable; for deep cold, Congtou is suitable. Cough must be distinguished as smooth or obstructed. If cough is obstructed, pathogen is constrained in the lung, requiring dispersion; use Jiegeng and Zhebei. If cough is smooth, regulating qi is suitable; use Suzi and Xingren. If wind-heat attacks the lung causing cough, use Sangye and Niubangzi. Food stagnation must be distinguished as caused by meat or grains. For grain stagnation, use Qu; for meat stagnation, use Shanzha. Summerheat must be distinguished as summerheat-dampness or summerheat-heat. For summerheat-dampness, use Xiangru and Guanghuo; for summerheat-heat, use Zhuye and Lugeng. As for malaria and dysentery, the causes are complex and changes are numerous, definitely beyond the scope of folk medicine. The proverb says, "If you don't believe in yin and yang, just listen to thunder; if you don't believe in medicine, just eat arsenic." My so-called folk medicine is just like that.
New Interpretation of Five Elements Theory. Within TCM itself, the Five Elements Theory is considered the most obscure and difficult thing to explain. Some understand it clearly in their minds but cannot express it verbally. If forced to speak, they sound like fortune tellers, saying a lot of irrelevant things, causing great suspicion.
For the general public, the Five Elements Theory is recognized as the most obscure and profound knowledge, far beyond ordinary understanding, leading them to view medicine as Buddhism or Daoist alchemy.
According to the former view, the Way is not understood; according to the latter view, the Way is not practiced. Since it cannot be understood or practiced, outsiders take advantage of this enthusiasm to attack, accusing us of mysticism, accusing us of not recognizing diseases, and accusing us of being unable to treat diseases. With tongues like reeds and pens like swords, they wag their tongues and shake their brushes, publishing wild claims in newspapers every day, confusing people and causing public unrest.
Metal, Wood, Water, Fire, and Earth are called the Five Elements. Heart, Liver, Spleen, Lung, and Kidney are called the Five Zang Organs. Why must the five zang organs of the human body correspond to the Five Elements? This is one question. Why must the Five Elements have mutual generation (Sheng) and mutual restriction (Ke)? This is another question. Why are the five zang organs closely related to the Five Elements? This is yet another question.
Each zang organ has its own movements and waxing/waning. The movements of the zang organs are called zang qi. Zang qi waxes and wanes. Without a way to describe them, how would we know the waxing and waning of zang qi? Therefore, Metal, Wood, Water, Fire, and Earth are synonyms for zang qi, and the mutual generation and restriction of the Five Elements are synonyms for the waxing and waning of zang qi. Every statement has evidence, and every event can be verified. Not a single word is mysticism or empty talk.
Why does the Lung belong to Metal? Let me tell you. In the Five Elements, Metal is called "Cong Ge" (following transformation). "Cong Ge" implies descending and purifying. Speaking of the Lung's zang qi, it originally governs through descending. Calling the Lung Metal simply signifies the descending nature of Lung qi, with absolutely no other mysterious meaning.
Why does the Liver belong to Wood? Let me tell you. In the Five Elements, Wood is called "Qu Zhi" (curving and straightening). "Qu Zhi" implies ascending and dispersing. Straight ascent is called "Zhi," and horizontal dispersal is called "Qu." Speaking of the Liver's zang qi, it originally functions through ascending and dispersing. Calling the Liver Wood simply signifies the ascending and dispersing nature of Liver qi, with absolutely no other mysterious meaning.
Why does the Heart belong to Fire? Let me tell you. In the Five Elements, Fire is called "Yan Shang" (flaming upward). "Yan Shang" means movement. Speaking of the Heart's zang qi, it originally functions through movement. Calling the Heart Fire simply signifies that Heart qi is active, with absolutely no other mysterious meaning elsewhere.
Why does the Kidney belong to Water? Let me tell you. In the Five Elements, Water is called "Run Xia" (moistening downward). "Run Xia" means stillness. Speaking of the Kidney's zang qi, it originally governs through stillness. Calling the Kidney Water simply signifies that Kidney qi is still, with absolutely no other mysterious meaning elsewhere.
Why does the Spleen belong to Earth? Let me tell you. In the Five Elements, Earth is called "Jia Se" (sowing and harvesting). "Jia Se" means harmony. What is harmony? To quote a classical phrase, "He" (Harmony) means not ascending nor descending, not moving nor stilling. It can also be said as both ascending and descending, both moving and stilling. This sentence seems contradictory. If it is not ascending nor descending, how can it be both ascending and descending? If it is not moving nor stilling, how can it be both moving and stilling? Actually, if it were truly not ascending nor descending and not moving nor stilling, it would become a dead entity. Therefore, the supplementary phrases "both ascending and descending, both moving and stilling" are indispensable. Enough idle talk, back to the subject. Speaking of the Spleen's zang qi, it originally governs through harmony. Calling the Spleen Earth simply signifies that Spleen qi harmonizes, with absolutely no other mystery.
Speaking of mutual generation and restriction is even easier. Since Lung qi descends, Kidney qi will not move recklessly. If Kidney qi does not move recklessly, it becomes still. This is Metal generating Water. Since the Kidney is still, Liver yin naturally nourishes. When Liver yin is nourished, the Liver finds its place. This is Water generating Wood. When Liver qi ascends and disperses, Heart yang receives assistance and naturally moves. This is Wood generating Fire. When Heart movement is intense, Spleen yang is naturally stimulated. When Spleen yang is stimulated, it naturally expands doubly. This is Fire generating Earth. When Spleen qi is harmonious, Lung descent encounters no obstruction. This is Earth generating Metal. Thus, so-called mutual generation simply means the qi of one zang organ helps the qi of another zang organ to grow. I will now speak plainly, without hiding secrets. Everyone should have some understanding of the Five Elements now.
Regarding mutual restriction: If Lung qi descends incessantly, it can restrain the ascending and dispersing of Liver qi. This is Metal restricting Wood. If Liver qi ascends and disperses incessantly, it can hinder the harmony of Spleen qi. This is Wood restricting Earth. If Spleen transportation is excessive, it can consume Kidney yin. This is Earth restricting Water. If Kidney qi is too still, it can suppress the floating of Heart qi from above. This is Water restricting Fire. If Heart qi is too active, it can hinder the descending of Lung qi. This is Fire restricting Metal. So-called mutual restriction simply means the qi of one zang organ is too strong, hindering the movement of another zang organ. In literary terms, this is mutual consumption. Mutual generation and restriction are merely synonyms for the waxing and waning of zang qi. Waxing is mutual generation; waning is mutual restriction.
Regarding diagnosis, mutual generation and restriction of the Five Elements are not needed for diagnosing exogenous diseases. Therefore, Zhang Zhongjing's *Treatise on Cold Damage* (*Shanghan Lun*) contains not a single word mentioning the mutual generation and restriction of the Five Elements. They are only useful when examining zang qi for treating miscellaneous diseases. Therefore, physicians who refute the Five Elements have not seen the true face of the Five Elements, and those who dazzle people with Five Elements generation and restriction when encountering diseases have also not seen the true face of the Five Elements.