论曰∶手足厥寒，脉细欲绝者，当归四逆汤主之。此症比诸四逆略轻。所以改用当归者
，在
一“细”字上勘出。诸四逆皆脉微，无言细者。微、细虽皆亡阳脉，而微为无气，细为无血
，其指不同。本论云下之后复发汗，脉微细。以微自汗来亡阳，细自下来亡阴。以彼例此，
细为血虚显然。《金匮》云∶血虚而厥，厥而必冒。是厥固有生于血虚者，故必以当归温经
，芍药治痹，而后血利；细辛开之，通草穿之，而后血流；其用桂枝者，取其散表寒也。方
意如是。论又曰∶下利强下之，脉浮革，因而肠鸣者，属当归四逆汤。浮革亦血虚之脉，肠
鸣亦血虚之因，又在利后，与此正足相参。此四逆症自属半表半里，《千金》谓为阳邪内陷
之治者得之。夫强下脉大，亦兼表耳！
释此散者，言人人殊，皆无确据。考《病源》寒食散发候云，皇甫曰寒食药者，世莫知
焉。
或曰华佗，或曰仲景。考之于实，佗之精微方类单省，而仲景经有侯氏黑散、紫石英方，皆
数种相出入，节度略同。然则寒食、草石二方，出自仲景，非佗也。据此，知侯氏黑散系石
发家服食之方，故有冷服填肠之说。石热之发，亦足召风，故入之中风。大约服石之风，创
于汉季，盛于隋唐。仲景传方而后，《外台》用此尤详。宋以来服石者鲜，此散几废。近喻
嘉言误指为中风主方，踵其说者，见其药不对症，未敢遵用，因专取菊花一味，以为本诸仲
景，而此方之义湮。详余所撰《经方例释》中。
案∶喻氏之意，以经文中有中风之论，而方止黑散数种耳！岂知中风自以续命为主方，
《外台》中明谓续命为仲景方，今《金匮》无者，脱也。详余所撰《金匮方论注》中。
论述说：手足寒冷，脉象细弱几乎要断绝的，用当归四逆汤主治。这个病症比一般的四逆证略轻。之所以改用当归，关键在于一个“细”字上推敲出来。一般的四逆证都是脉微，没有提到脉细的。微脉和细脉虽然都属于亡阳的脉象，但微脉代表气虚，细脉代表血虚，它们的指征是不同的。本论中说：下法之后又发汗，脉象微细。其中微脉是因为发汗导致亡阳，细脉是因为下法导致亡阴。以此类推，这里的细脉显然是血虚的表现。《金匮要略》说：血虚而厥逆，厥逆必然伴有头目昏眩。这说明厥逆确实有由血虚引起的，所以必须用当归来温通经脉，芍药治疗痹阻，这样血液才能流通；细辛宣通阳气，通草疏通经络，这样血流才能顺畅；使用桂枝的原因，是取其发散表寒的作用。方剂的用意就是这样。
论述又说：腹泻时强行攻下，脉象浮而革（外强中空），因而出现肠鸣的，属于当归四逆汤证。浮革脉也是血虚的脉象，肠鸣也是血虚导致的症状，而且这种情况发生在泻下之后，与此处的情况正好可以互相参照。这种四逆证自然属于半表半里证，《千金方》称其为阳邪内陷的治疗方法，这是正确的。如果强行攻下后脉大，也兼有表证！
解释侯氏黑散的人，说法各不相同，都没有确凿的依据。考证《诸病源候论·寒食散发候》记载，皇甫士安说寒食药，世人都不知晓。有人说出自华佗，有人说出自张仲景。根据实际考察，华佗的精妙方剂大多简单精简，而张仲景的经方中有侯氏黑散、紫石英方，都包含多种药物，出入变化大致相同。既然这样，那么寒食散、草石二方，出自张仲景，而非华佗。据此可知，侯氏黑散是服用石药的人服食的方子，所以有冷服以填塞肠胃的说法。石药热毒发作，也容易招致风邪，所以加入治疗中风的药物。大概服用石药引发的风证，创始于汉代末年，兴盛于隋唐时期。张仲景传下方剂之后，《外台秘要》对此记载尤为详细。宋代以来服用石药的人很少，这个方子几乎被废弃。近代喻嘉言错误地将其指认为中风的主方，追随他说法的人，看到其药物与症状不对应，不敢遵照使用，于是专门选取菊花一味药，认为这才是符合张仲景原意的，从而导致此方的本义湮没无闻。详见我撰写的《经方例释》中。
按语：喻氏的意思，是因为经文中有中风的论述，而方子只有黑散等几种药！哪里知道治疗中风自应以续命汤为主方，《外台秘要》中明确说明续命汤是张仲景的方子，现在《金匮要略》中没有收录，是脱漏了。详见我撰写的《金匮方论注》中。
It is stated in the treatise: "For coldness of the hands and feet, with a fine pulse that seems on the verge of disappearing, Danggui Sini Tang (Angelica Sinensis Decoction for Extremity Cold) is the primary formula." This syndrome is slightly milder than typical Sini patterns. The reason for substituting Danggui lies in the character "fine" (xi). In all other Sini patterns, the pulse is typically "minute" (wei), without mention of being "fine." Although both minute and fine pulses belong to the category of Yang depletion, a minute pulse indicates Qi deficiency, whereas a fine pulse indicates Blood deficiency; their indications differ. The treatise states: "After purgation followed by sweating, the pulse becomes minute and fine." The minute aspect arises from sweating leading to Yang depletion, while the fine aspect arises from purgation leading to Yin depletion. By analogy, the fine pulse here clearly indicates Blood deficiency. *Jingui Yaolue* states: "Blood deficiency leads to Jue (extremity cold); Jue inevitably involves Mao (dizziness/vertigo)." Thus, Jue can indeed originate from Blood deficiency. Therefore, Danggui must be used to warm the meridians, and Shaoyao (White Peony Root) to treat Bi (obstruction), so that the Blood may flow freely; Xixin (Asarum) opens the pathways, Tongcao (Tetrapanax Pith) penetrates them, so that blood circulation is unimpeded; the use of Guizhi (Cinnamon Twig) is to disperse exterior Cold. Such is the intent of the formula.
The treatise further states: "If diarrhea occurs and aggressive purgation is applied, resulting in a floating and革 (ge, like a drum skin) pulse, accompanied by borborygmus (intestinal rumbling), it belongs to the Danggui Sini Tang pattern." A floating-ge pulse is also indicative of Blood deficiency, and borborygmus is a consequence of Blood deficiency. Moreover, this occurs after purgation, which corresponds perfectly with the previous discussion for mutual reference. This type of Sini pattern naturally belongs to the Shaoyang (Half-Exterior, Half-Interior) stage. *Qianjin Fang* describes it as a treatment for Yang pathogenic factors sinking inward, which is correct. If aggressive purgation results in a large pulse, it also implies an accompanying Exterior syndrome!
Regarding the explanation of Hou's Black Powder (Houshi Heisan), opinions vary widely, yet none possess solid evidence. Examining *Zhubing Yuanhou Lun* (General Treatise on the Pathogenesis and Manifestations of All Diseases) under "Cold Food Disorder," Huangfu Mi states that the "Cold Food Medicine" is unknown to the world. Some attribute it to Hua Tuo, others to Zhang Zhongjing. Based on factual examination, Hua Tuo's refined prescriptions were generally simple and concise, whereas Zhang Zhongjing's canonical formulas include Hou's Black Powder and Zhi Shiyang Formula, both comprising multiple ingredients with similar variations and regulations. Therefore, the Cold Food Powder and the Grass-Stone formulas originated from Zhang Zhongjing, not Hua Tuo. From this, we know that Hou's Black Powder was a prescription taken by those consuming Stone Medicines (mineral pills), hence the saying about taking it cold to fill the intestines. The heat toxicity from stone medicines often invites Wind pathogens, thus incorporating treatments for Wind-stroke. Generally, wind syndromes induced by stone medicine consumption began in the late Han Dynasty and flourished during the Sui and Tang Dynasties. After Zhang Zhongjing transmitted his formulas, *Waitai Miyao* recorded their use in detail. Since the Song Dynasty, few have consumed stone medicines, causing this powder to nearly fall into oblivion. Recently, Yu Jiayan erroneously identified it as the principal formula for Wind-stroke. Followers of this view, seeing that the herbs did not match the symptoms, dared not follow it, and instead selected only Chrysanthemum (Juhua), claiming it aligned with Zhang Zhongjing's principles, thereby obscuring the true meaning of this formula. See my detailed discussion in *Jingfang Lishi*.
Note: Yu's intention was that since the text mentions Wind-stroke, but the formula contains only a few types of herbs in the Black Powder! How could he know that the principal formula for Wind-stroke should be Xuming Tang? *Waitai Miyao* explicitly states that Xuming Tang is a formula of Zhang Zhongjing. Its absence in *Jingui Yaolue* is due to textual loss. See my detailed commentary in *Jingui Fanglun Zhu*.