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.