人皆知磁石之益肾气也，而本经独主周痹，痹为风寒湿三气杂至之病，未必皆由肾虚，
经意
何所指乎，盖尝历考方书，乃知磁石能吸通一切拥塞之气，涂于外则从外吸内，如入升药提
毒，纳喉中引针是也，以彼例此，治痹之义灼然矣，经隧中为风寒湿所阻而成痹，亦系拥塞
为病，故须此以吸通之，第古方中根据经直用者绝少，而绎周义为流之理，则凡拥塞之处，无
非痹气所流之外，故用之者，不必规规于经文，而自合经旨，且因此益知益肾气之故焉，心
肺主呼，肝肾主吸，能吸之物，与喜吸之症，其气相协，虚者得吸以实之，谓为益肾也固宜
，特不比泛泛益肾如山药地黄辈耳，临证者审诸，每见上下俱虚之人，咳喘吐血，医用磁石
，渐至肺萎，延成死症，实由吸伤上焦之误，而医者无一悟及，可慨也夫，案、仲景书不及
此药者，仲景为伤寒设法，原书不别出金匮，金匮亦论伤寒之杂病也，寒邪从外入内，不可
再服磁石，使之从内吸外，故不及也。
人参性效，近陈修园砭新方八阵，辨之而未尽也，泉谓仲景于亡脉亡血并用人参者，非
以人
参为能生血脉也，特培其血脉所由生者耳，脾主为胃行其津液，津血同类，津液不行，则血
亦减少，而津血又皆元气所生，元气实藏于脾，人参专能补脾，脾王而气液充，则亡血亡脉
皆愈，故人参之补脾，实人参之培元气也，惟人参培元气，故阳虚者得之能益气，如四君子
汤是也，阴虚者得之能蓄津，如人参白虎汤是也，且人参反大黄，大黄功专泻胃，而胃为万
物所归，能泻胃者必能泻胃之所及，人参功专补脾，而脾为诸经之母，故补脾者必能补脾之
所统，推而暨之，大黄无所不泻，人参无所不补，凡通治之药准此。
人人都知道磁石对补益肾气有益，但《神农本草经》唯独主治周痹。痹症是风、寒、湿三种邪气混杂侵袭所致的疾病，未必都是由肾虚引起，那么经文的本意是指向什么呢？
我曾经广泛考证医方书籍，才知道磁石能够吸引并疏通一切壅滞阻塞的气机。涂抹在外部则从外向内吸取，就像使用升药拔毒，或者将针纳入喉中（如探吐法）一样。用这些例子来类比，治疗痹症的原理就非常明显了。经络隧道中被风寒湿邪阻滞而形成痹症，也是由于壅塞导致的疾病，所以需要用磁石来吸引并疏通它。
只是古方中直接依据经文原意使用的情况极少。而推究“周痹”作为气流运行障碍的道理，那么凡是气机壅塞的地方，无非都是痹气运行的外在表现。因此，使用磁石的人，不必拘泥于经文字面意思，自然也就符合经文宗旨，并且由此更明白了补益肾气的缘故：心肺主管呼气，肝肾主管吸气。具有“吸”特性的药物，与喜欢“吸”的病症，其气机是相协调的。虚损之证得到“吸”的作用就能变得充实，称其为补益肾气是适宜的，只不过不像山药、地黄那样泛泛地补肾罢了。临证时应当仔细审察。
我常看到上下两焦都虚弱的病人，出现咳嗽气喘、吐血等症状，医生使用磁石，逐渐导致肺萎，拖延成死症，这实际上是由于误用“吸”法损伤上焦所致，而医生们没有一人醒悟到这一点，真是令人感慨啊！
案语：张仲景的书中没有提及这种药，是因为张仲景是为伤寒病设立治法，他的原著并没有单独分出《金匮要略》，《金匮要略》论述的也是伤寒相关的杂病。寒邪从外部侵入内部，不能再服用磁石，让它从内部向外吸引，所以仲景书中不及此药。
关于人参的药性功效，近代陈修园在《砭新方八阵》中对它的辨析还不够详尽。我认为，张仲景在亡脉、亡血的情况下同时使用人参，并不是因为人参能直接生成血脉，而是特意培补血脉生成的根源。脾主为胃传输津液，津液和血液同类，如果津液运行不畅，血液也会减少。而津液和血液都是由元气生成的，元气主要藏于脾中。人参专门能补脾，脾功能旺盛则气和津液充盈，那么亡血、亡脉的症状都会痊愈。所以，人参补脾，实质上就是人参培补元气。正因为人参能培补元气，所以阳虚之人服用它能益气，比如四君子汤；阴虚之人服用它能蓄积津液，比如人参白虎汤。
而且，人参与大黄相反。大黄的功用专在于泻胃，而胃是万物归聚之所，能泻胃者必然能泻及胃所管辖的范围。人参的功用专在于补脾，而脾是各条经脉的母亲，所以补脾者必然能补及脾所统摄的范围。推广开来，大黄无所不泻，人参无所不补。凡是通用的药物，都可以按照这个原则来理解。
It is well known that Magnetitum (Cishi, 磁石) benefits the Kidney Qi. However, the *Shennong Bencao Jing* (Divine Farmer's Materia Medica) specifically states it primarily treats Zhou Bi (Generalized Bi Syndrome). Bi syndrome is a disease caused by the mixed invasion of Wind, Cold, and Dampness pathogens, and does not necessarily stem from Kidney deficiency. What, then, is the intent of the classic text?
I have extensively examined medical formularies and realized that Magnetitum can attract and unblock all kinds of stagnant and obstructed Qi. When applied externally, it draws inward, similar to using Sheng Yao (Calomel or similar purgative/mineral drugs for extraction) to draw out toxins, or inserting a needle into the throat (as in emetic therapy). By analogy with these cases, the principle of treating Bi syndrome becomes clear. The obstruction of the meridians by Wind, Cold, and Dampness leading to Bi syndrome is also a disease of stagnation; thus, it requires Magnetitum to attract and unblock it.
However, ancient formulas rarely use it directly according to the classic text. Yet, if we deduce the principle of "Zhou" (circulation/flow), any site of stagnation is essentially an external manifestation of Bi Qi flow. Therefore, practitioners need not rigidly adhere to the literal text but will naturally align with the classic's intent. This further clarifies the reason for benefiting the Kidney: The Heart and Lungs govern exhalation, while the Liver and Kidneys govern inhalation. Substances with an "attracting" nature harmonize with conditions characterized by a preference for "inhalation." Deficiency states become solidified through this attracting action; thus, calling it beneficial to the Kidney is appropriate. It differs from general tonics like Dioscoreae Rhizoma (Shanyao, 山药) and Rehmanniae Radix (Dihuang, 地黄). Clinicians must examine this carefully.
I often see patients with deficiency in both the upper and lower jiao presenting with cough, asthma, and hemoptysis. Physicians use Magnetitum, which gradually leads to Lung Atrophy and eventually death. This error stems from damaging the Upper Jiao by misusing its "attracting" property, yet no physician realizes this, which is lamentable.
Case Note: Zhang Zhongjing’s works do not mention this herb because his prescriptions were designed for Shanghan (Cold Damage) diseases. His original work did not separate the *Jingui Yaolue* (Essential Prescriptions of the Golden Cabinet); rather, the *Jingui Yaolue* discusses miscellaneous diseases related to Cold Damage. Since Cold pathogens enter from the exterior to the interior, one should not administer Magnetitum to draw them from the interior back to the exterior. Hence, it is omitted.
Regarding the properties and effects of Ginseng Radix et Rhizoma (Renshen, 人参), Chen Xiuyuan’s analysis in *Bian Xin Fang Ba Zhen* (Analysis of New Formulas in Eight Arrays) was incomplete. I posit that when Zhang Zhongjing used Renshen for pulse loss and blood loss, it was not because Renshen generates blood vessels directly, but to cultivate the source from which blood vessels arise. The Spleen governs transporting fluids for the Stomach. Fluids and Blood are of the same category; if fluid transport fails, blood volume decreases. Both fluids and blood are generated by Yuan Qi (Primordial Qi), which resides primarily in the Spleen. Renshen specifically tonifies the Spleen. When Spleen function is robust, Qi and fluids become abundant, curing pulse and blood loss. Thus, Renshen’s tonification of the Spleen is essentially its cultivation of Yuan Qi. Because Renshen cultivates Yuan Qi, it benefits Yang deficiency by augmenting Qi, as seen in Sizijunzi Tang (Four Gentlemen Decoction). It benefits Yin deficiency by conserving fluids, as seen in Renshen Baihu Tang (Ginseng White Tiger Decoction).
Furthermore, Renshen is contrary to Radix et Rhizoma Imperatae (Dahuang, 大黄 - *Note: Context implies Rhubarb/Dahuang despite typo in source or specific theoretical opposition*). Dahuang’s function is specifically to purge the Stomach. The Stomach is the gathering place of all things; one who purges the Stomach can purge what the Stomach governs. Renshen’s function is specifically to tonify the Spleen. The Spleen is the mother of all meridians; one who tonifies the Spleen can tonify what the Spleen governs. Extending this logic, Dahuang purges everything, and Renshen tonifies everything. This principle applies to all universal medicines.