手足厥冷，脉细欲绝者，当归四逆汤主之。
上编论外热内寒，兼吐利呕逆烦躁等证。此篇但论厥阴脉证，虽无外卫之微阳，亦未见内寒诸险证也。
当归四逆汤∶
当归 桂枝 芍药 细辛（各三两） 甘草（炙） 通草（各二两） 大枣（二十五枚，擘一法十二枚）
上七味，以水八升，煮取三升，去滓，温服一升，日三服。
此条证为在里，当是四逆本方加当归，如茯苓四逆之例。若反用桂枝汤攻表，误矣。既名四逆汤，岂得无姜、
附？
若其人内有久寒者，宜当归四逆加吴茱萸生姜汤。
当归四逆加吴茱萸生姜汤∶
即前方加吴茱萸（一两），生姜（半斤，切片）。
上九味，以水六升，清酒六升和煮，取五升，去滓，温分
五服。
此本是四逆与吴茱萸相合而为偶方也。吴萸配附子，生姜佐干姜，久寒始去。
凡厥者，阴阳气不相顺接，便为厥。厥者，手足逆冷是也。
手足六经之脉，皆自阴传阳，自阳传阴。阴气胜，则阳不达于四肢，故为寒厥。
诸四逆厥者，不可下之，虚家亦然。
热厥者，有可下之理；寒厥为虚，则宜温补。
伤寒五六日，不结胸，腹濡脉虚，复厥者，不可下。此为亡血，下之死。
其脉空虚，此无血也。
病者，手足厥冷，言我不结胸，小腹满，按之痛者，此冷结在膀胱关元也。
关元在脐下三寸，小肠之募，三阴任脉之会，宜灸之。按此二条，当知结胸证有热厥者。
伤寒脉促，手足厥者，可灸之。
促为阳脉，亦有阳虚而促者，亦有阴盛而促者。要知促与结皆代之互文，皆是虚脉。火气虽微，内攻有力，
故灸之。
伤寒六七日，脉微，手足厥冷，烦躁，灸厥阴。厥不还者死。
厥阴肝脉也，应春生之气，故灸其五俞而阳可回也。
上论厥阴脉证。
发汗，若下之，病仍不解，烦躁者，茯苓四逆汤主之。
未经汗下而烦躁，为阳盛；汗下后而烦躁，是阳虚。汗多既亡阳，下多又亡阴，故热仍不解。姜、附以回阳，
参、苓以滋阴，则烦躁止而外热自除，此又阴阳双补法。
茯苓四逆汤∶
茯苓（四两） 人参（一两） 附子（一枚，去皮生用切八片） 甘草（二两，炙） 干姜（一两五钱）
上五味，以水五升，煮取三升，去滓，温服七合，日二服。
下后复发汗，昼日烦躁不得眠，夜而安静，不呕不渴，无表证，脉沉微，身无大热者，干姜附子汤主之。
当发汗而反下之，下后不解，复发其汗，汗出而里阳将脱，故烦躁也。昼日不得眠，虚邪独据于阳分也。夜
而安静，知阴不虚也。不呕渴，是无里热；不恶寒头痛，是无表证。脉沉微，是纯阴无阳矣；身无大热，表阳将
去矣。幸此微热未除，烦躁不宁之际，独任干姜、生附，以急回其阳，此四逆之变剂也。
干姜附子汤∶
干姜（一两） 附子（一枚，去皮生用切八片）
上二味，以水三升，煮取一升，去滓顿服。
下之后复发汗，必振寒，脉微细。所以然者，内外俱虚故也。
内阳虚，故脉微细，外阳虚，故振栗恶寒，即干姜附子证。
上论四逆加减证。
Coldness of the hands and feet, with a fine pulse nearly imperceptible, should be treated with Danggui Sini Decoction (Angelica Sinensis Decoction for Cold Extremities).
The preceding chapter discussed exterior heat and interior cold, accompanied by symptoms such as vomiting, diarrhea, nausea, and irritability. This chapter only discusses the pulse and syndromes of the Jueyin (Terminal Yin) channel. Although there is no slight Yang deficiency in the defensive layer, nor are there various dangerous signs of interior cold.
Danggui Sini Decoction:
Danggui (Radix Angelicae Sinensis), Guizhi (Ramulus Cinnamomi), Shaoyao (Radix Paeoniae Rubra or Radix Paeoniae Alba), Xixin (Herba Asari), each three liang; Zhigancao (Radix Glycyrrhizae Preparata), Tongcao (Medulla Tetrapanacis), each two liang; Dazao (Fructus Jujubae), twenty-five pieces, split open (in another method, twelve pieces).
These seven ingredients are decocted in eight sheng of water to obtain three sheng of liquid. The dregs are removed, and one sheng is taken warm, three times daily.
This syndrome belongs to the interior. It should be the original Sizini Tang (Four Counterflow Decoction) with added Danggui, similar to the example of Fuling Sizini Tang (Poria Four Counterflow Decoction). If one were to mistakenly use Guizhi Tang (Cinnamon Twig Decoction) to attack the exterior, it would be an error. Since it is named Sizini Tang, how could it lack Ganjiang (Rhizoma Zingiberis Preparata) and Fuzi (Radix Aconiti Lateralis Preparata)?
If the patient has long-standing cold within, Danggui Sini Tang plus Wuzhuyu and Shengjiang Decoction (Danggui Sini Decoction with Evodia and Fresh Ginger) is appropriate.
Danggui Sini Tang plus Wuzhuyu and Shengjiang Decoction:
This is the previous formula plus Wuzhuyu (Fructus Evodiae, one liang) and Shengjiang (Rhizoma Zingiberis Recens, half a jin, sliced).
These nine ingredients are decocted together with six sheng of water and six sheng of clear wine to obtain five sheng of liquid. The dregs are removed, and the liquid is divided into five warm doses.
This was originally an even pairing of Sizini Tang combined with Wuzhuyu. Wuzhuyu paired with Fuzi, and Shengjiang assisting Ganjiang, allows for the removal of long-standing cold.
In all cases of Jue (Counterflow Cold), the Qi of Yin and Yang fails to connect smoothly, which constitutes Jue. Jue refers to the counterflow coldness of the hands and feet.
The meridians of the six channels of the hands and feet transmit from Yin to Yang, and from Yang to Yin. When Yin Qi prevails, Yang cannot reach the four limbs, thus resulting in Cold Jue.
For all cases of Sizhi Jue (Counterflow Cold), purgation is contraindicated, and this applies equally to patients with deficiency constitutions.
In cases of Heat Jue, there is a rationale for using purgation; however, Cold Jue is due to deficiency, so warming and tonification are appropriate.
In Shanghan (Cold Damage) lasting five or six days, without chest binding (Jie Xiong), with a soft abdomen and a deficient pulse, if Jue recurs, purgation is contraindicated. This is due to blood loss; purgation would lead to death.
An empty pulse indicates a lack of blood.
When a patient presents with coldness of the hands and feet, states that they do not have chest binding, and has fullness and tenderness upon pressure in the lower abdomen, this indicates cold binding at the Bladder's Guan Yuan (CV4) point.
Guan Yuan is located three cun below the umbilicus, it is the Mu-Alarm point of the Small Intestine, and the convergence of the Three Yin channels and the Ren Mai (Conception Vessel). Moxibustion is appropriate. Based on these two clauses, one should understand that among chest binding syndromes, there are cases of Heat Jue.
In Shanghan, if the pulse is rapid (Cu) and the hands and feet are cold, moxibustion may be applied.
A rapid pulse is a Yang pulse, but it can also occur due to Yang deficiency or Yin excess. One must know that "rapid" and "intermittent" (Dai) pulses are often used interchangeably in context, both indicating a deficient pulse. Although the power of fire is slight, its internal attack is potent; therefore, moxibustion is used.
In Shanghan lasting six or seven days, with a faint pulse, cold hands and feet, and irritability, moxibustion should be applied to the Jueyin channel. If Jue does not reverse, the patient will die.
The Jueyin channel corresponds to the Liver and follows the Qi of spring generation; therefore, moxibustion on its Five Shu points allows Yang to return.
The above discusses the pulse and syndromes of the Jueyin channel.
After sweating or purging, if the disease remains unresolved and irritability occurs, Fuling Sizini Tang (Poria Four Counterflow Decoction) should be administered.
Irritability without prior sweating or purging indicates excess Yang; irritability after sweating and purging indicates Yang deficiency. Excessive sweating depletes Yang, while excessive purging depletes Yin, so the heat remains unresolved. Ganjiang and Fuzi restore Yang, while Renshen and Fuling nourish Yin; thus, irritability ceases and exterior heat is naturally eliminated. This is another method of dual tonification of Yin and Yang.
Fuling Sizini Tang:
Fuling (Poria), four liang; Renshen (Radix Ginseng), one liang; Fuzi (Radix Aconiti Lateralis Preparata), one piece, peeled, raw, cut into eight slices; Zhigancao (Radix Glycyrrhizae Preparata), two liang; Ganjiang (Rhizoma Zingiberis Preparata), one liang five qian.
These five ingredients are decocted in five sheng of water to obtain three sheng of liquid. The dregs are removed, and seven he are taken warm, twice daily.
After purging followed by sweating, if the patient experiences irritability during the day preventing sleep, but remains quiet at night, without vomiting or thirst, without exterior syndrome, with a deep and faint pulse, and without significant body heat, Ganjiang Fuzi Tang (Dried Ginger and Aconite Decoction) should be administered.
When sweating should have been performed but purging was mistakenly used, and the disease persists after purging, subsequent sweating leads to sweat loss and impending collapse of interior Yang, causing irritability. Inability to sleep during the day indicates that deficient pathogenic factors occupy the Yang aspect. Quietness at night indicates that Yin is not deficient. Absence of vomiting and thirst indicates no interior heat; absence of aversion to cold and headache indicates no exterior syndrome. A deep and faint pulse indicates pure Yin without Yang; absence of significant heat indicates that exterior Yang is departing. Fortunately, since a slight heat remains, amidst the irritability, relying solely on Ganjiang and raw Fuzi urgently restores Yang. This is a modified form of Sizini Tang.
Ganjiang Fuzi Tang:
Ganjiang (Rhizoma Zingiberis Preparata), one liang; Fuzi (Radix Aconiti Lateralis Preparata), one piece, peeled, raw, cut into eight slices.
These two ingredients are decocted in three sheng of water to obtain one sheng of liquid. The dregs are removed, and the entire dose is taken at once.
After purging followed by sweating, chills and a faint, fine pulse inevitably occur. This is because both interior and exterior are deficient.
Interior Yang deficiency causes a faint and fine pulse; exterior Yang deficiency causes trembling and aversion to cold, which is the syndrome for Ganjiang Fuzi Tang.
The above discusses the modified syndromes of Sizini Tang.