凡致病必有因，因受病之处则各有部位。今之医者曰∶病必分经络而后治之。似矣，然
亦知
病固非经络之所能尽者乎？夫人有皮肉筋骨以成形，所谓躯壳也。而虚其中，则有脏腑以实
之。其连续贯通者，则有经有络贯乎脏腑之内，运乎躯壳之中，为之道路，以传变周流者也
。故邪之伤人，或在皮肉，或在筋骨，或在脏腑，或在经络。有相传者，有不相传者，有久
而相传者，有久而终不传者。其大端则中于经络者易传；其初不在经络，或病甚而流于经络
者，亦易传。经络之病，深入脏腑，则以生克相传。惟皮肉筋骨之病，不归经络者，则不传
，所谓躯壳之病也。故识病之人，当直指其病在何脏何腑，何筋何骨，何经何络，或传或不
传， 传以何经始，以何经终。其言历历可验，则医之明者矣。今人不问何病，廖举一经以
借口，以见其颇识《内经》，实与《内经》全然不解也。至治之难易，则在经络易治，在脏
腑者难治，且多死。在皮肉筋骨者难治，亦不易死。其大端如此。至于躯壳脏腑之属于某经
络，以审其针灸用药之法，则《内经》明言之，深求自得也。
欲知病之难易，先知病之浅深。欲知病之浅深；先知病之部位。夫人身一也，实有表里
上下
之别焉。何谓表？皮肉筋骨是也。何谓里？ 脏腑精神是也。而经络则贯乎其间。表之病易治
而难死，里之病难治而易死。此其大略也。而在表在里者，又各有难易，此不可执一而论也
。若夫病本在表，而传于里；病本在里，而并及于表。是为内外兼病，尤不易治。身半已上
之病，往往近于热；身半以下之病，往往近于寒。此其大略也。而在上在下，又各有寒热，
此亦不可执一而论也。若夫病本在上，而传于下，病本在下，而传于上，是之谓上下兼病，
亦不易治。所以然者，无病之处多，有病之处少，则精力犹可维持，使正气渐充，而邪气亦
去。若夫一人之身，无处不病，则以何者为驱病之本，而复其元气乎？故善医者，知病势之
盛而必传也，预为之防，无使结聚，无使泛滥，无使并合，此上工治未病之说也。若其已至
于传，则必先求其本，后求其标，相其缓急而施治之。此又桑榆之收也。以此决病之生死难
易，思过半矣。
凡是致病因素，必定有其原因，而病因所侵袭的部位也各有不同。现在的医生常说：治病必须分清经络才能治疗。这似乎有道理，然而他们也知道疾病并不完全局限于经络所能涵盖的范围吗？人拥有皮、肉、筋、骨来构成形体，这就是所谓的“躯壳”。而在躯壳内部空虚之处，则有脏腑来充实它。连接贯通的，则有经和络贯穿在脏腑之内，运行于躯壳之中，作为道路，使气血传变周流全身。所以邪气伤害人体，可能在皮肉，可能在筋骨，可能在脏腑，可能在经络。有的会相互传变，有的不会相互传变；有的经过长时间才传变，有的经过长时间最终也不传变。其大致规律是：病邪中于经络的容易传变；起初不在经络，或者病情严重而波及到经络的，也容易传变。如果经络的病深入脏腑，就会按照五行生克的规律相互传变。只有那些病在皮肉筋骨，而不归入经络的，则不会传变，这就是所谓的“躯壳之病”。因此，善于识病的医生，应当明确指出病在哪个脏、哪个腑、哪条筋、哪块骨、哪条经、哪条络，判断是会传变还是不会传变，传变从哪条经开始，以哪条经结束。如果医生的论述清晰可验证，那就是高明的医生了。现在的人不问是什么病，就胡乱举出一条经络作为借口，以此显示自己颇懂《黄帝内经》，这实际上是完全不懂《黄帝内经》。至于治疗的难易程度，病在经络的容易治疗，病在脏腑的难治，且多导致死亡。病在皮肉筋骨的难治，但也较不容易死亡。这是大致的情况。至于躯壳和脏腑归属于某条经络，从而审定针灸和用药的方法，《黄帝内经》中有明确说明，深入探究自然会有心得。
想要知道疾病的难易，先要知道疾病的浅深。想要知道疾病的浅深，先要知道疾病的部位。人的身体虽然是一个整体，但确实有表里上下的区别。什么叫表？就是皮、肉、筋、骨。什么叫里？就是脏腑和精神。而经络则贯穿在表里之间。在表的病容易治疗且不易死亡，在里的病难治且易死亡。这是大概的情况。然而在表和里的病，又各自有难易之分，这是不能一概而论的。如果病本来在表，却传变到了里；病本来在里，却同时波及到表。这就叫做内外兼病，尤其不容易治疗。身体上半部分的病，往往偏热；身体下半部分的病，往往偏寒。这是大概的情况。然而在上和在下，又各自有寒热之分，这也是不能一概而论的。如果病本来在上，却传变到了下；病本来在下，却传变到了上，这就叫做上下兼病，也不容易治疗。之所以这样，是因为没有生病的地方多，生病的地方少，那么精力还可以维持，使得正气逐渐充盛，邪气也能去除。如果一个人的身体，无处不病，那么以什么作为驱除病邪的根本，并恢复元气呢？所以高明的医生，知道病势旺盛且必然传变时，预先加以防范，不让病邪结聚，不让病邪泛滥，不让病邪合并，这就是上工（高明医生）“治未病”的说法。如果病已经发生传变，那就必须先探求病本，后处理病标，观察病情的缓急来实施治疗。这又是事后补救的措施。用这些原则来判断疾病的生死难易，思考就已经超过一半了。
All pathogenic factors must have a cause, and the location where the disease is contracted varies. Contemporary physicians often state: "Treatment must be based on distinguishing the meridians." This seems plausible; however, do they also realize that diseases are not entirely confined to what can be explained by meridians? The human body possesses skin, flesh, tendons, and bones to form its structure, which is referred to as the "body shell" (Qiao Ke). Within this hollow interior, Zang-Fu organs (viscera) reside to fill it. Connecting and penetrating through these structures are the Jing (Meridians) and Luo (Collaterals), which run within the Zang-Fu organs and throughout the body shell, serving as pathways for the circulation and transformation of Qi and Blood. Therefore, when pathogenic factors invade the human body, they may affect the skin and flesh, the tendons and bones, the Zang-Fu organs, or the meridians. Some conditions transmit to other areas, while others do not; some transmit after a long period, while others never transmit despite the passage of time. The general principle is that diseases affecting the meridians are prone to transmission; those initially not in the meridians, or those severe enough to spread into the meridians, are also prone to transmission. If meridian diseases penetrate deeply into the Zang-Fu organs, they transmit according to the Five Elements generation and restriction cycles. Only diseases located in the skin, flesh, tendons, and bones that do not involve the meridians will not transmit; these are termed "diseases of the body shell." Thus, a skilled physician should clearly identify the specific Zang, Fu, tendon, bone, meridian, or collateral involved, determine whether transmission will occur, and trace the starting and ending meridians of any transmission. If such diagnoses are clear and verifiable, the physician is considered enlightened. Today's practitioners, regardless of the actual disease, arbitrarily cite a single meridian as an excuse to appear knowledgeable about the *Huangdi Neijing* (Yellow Emperor's Inner Canon); this demonstrates a complete misunderstanding of the text. Regarding treatment difficulty, diseases in the meridians are easier to treat, whereas diseases in the Zang-Fu organs are difficult to treat and often fatal. Diseases in the skin, flesh, tendons, and bones are difficult to treat but less likely to result in death. These are the general rules. As for determining acupuncture and herbal therapy methods based on which meridians govern the body shell and Zang-Fu organs, the *Huangdi Neijing* states this explicitly, and deep study yields understanding.
To know the ease or difficulty of treating a disease, one must first know its depth. To know the depth, one must first know its location. Although the human body is a unity, there are distinct differences between exterior/interior and upper/lower. What constitutes the Exterior? It is the skin, flesh, tendons, and bones. What constitutes the Interior? It is the Zang-Fu organs and Spirit (Shen). The meridians penetrate between them. Diseases in the Exterior are easier to treat and less likely to be fatal; diseases in the Interior are difficult to treat and more likely to be fatal. This is the general overview. However, both Exterior and Interior diseases have varying degrees of difficulty, so one cannot apply a rigid rule. If a disease originates in the Exterior but transmits to the Interior, or originates in the Interior and simultaneously affects the Exterior, this is called "combined Exterior-Interior disease," which is particularly difficult to treat. Diseases in the upper half of the body tend toward Heat; diseases in the lower half tend toward Cold. This is the general rule. Yet, both Upper and Lower regions can present with either Cold or Heat patterns, so again, one cannot generalize rigidly. If a disease originates in the Upper part but transmits to the Lower, or originates in the Lower and transmits to the Upper, this is called "combined Upper-Lower disease," which is also difficult to treat. The reason is that if healthy areas outnumber diseased areas, vital energy (Jing-Qi) can still maintain balance, allowing Zheng Qi (Upright Qi) to gradually strengthen and eliminate Xie Qi (Pathogenic Qi). However, if the entire body is diseased, what serves as the foundation for expelling pathogens and restoring Yuan Qi (Original Qi)? Therefore, superior physicians, recognizing that intense pathogenic forces inevitably transmit, take preventive measures beforehand: preventing stagnation, preventing spreading, and preventing consolidation. This aligns with the concept of "treating disease before it arises" advocated by Shang Gong (Superior Physicians). If transmission has already occurred, one must first address the root (Ben) and then the branch (Biao), applying treatment according to the urgency of the condition. This represents remedial action after the fact. By applying these principles to judge the prognosis and difficulty of diseases, one has grasped the majority of the essential concepts.