The Neishu Huanglian Tang (Internal Draining Coptis Decoction) should be administered urgently to promote circulation and unblock stagnation. Furthermore, when a disease has persisted for a long time, with pathogenic factors and healthy qi resisting each other, the primordial qi (Yuan Qi) will inevitably become deficient. Even if there are residual symptoms, miscellaneous diseases, or deteriorated conditions, one must first consolidate the root (Ben), and subsequently regulate, harmonize, and disperse them. This allows the pathogenic qi to gradually recede, the primordial qi to gradually awaken, dietary intake to gradually increase, and the foundation to gradually strengthen. Under these circumstances, there is no reason why remaining ailments cannot be cured. This is what is meant by "when the momentum is isolated, defend; when the root is established, the Way arises." It is common to see practitioners who, regardless of whether the disease is new or old, or whether the root qi is strong or weak, fail to comprehend that deficiency can cause disease and disease can cause deficiency, and further fail to distinguish between deficiency-heat and deficiency-cold. They blindly apply attacking treatments in all cases, akin to a blind man riding a blind horse at midnight near a deep pool, surely leading to danger.

Medicines must seek the root and branch; no efficacy is clearer than distinguishing the order of treatment. If tonification and purgation are applied indiscriminately, errors may occur in both approaches.

All things have roots and branches, but the root and branch of bodily diseases are particularly significant. Speaking of the root and branch of Heaven and Earth's Qi dynamics: the Five Movements (Wu Yun) are the root, and the Six Qi (Liu Qi) are the branch. This is how one participates in the transformation and nourishment of Heaven and Earth, clarifies the generation and restriction of the Five Phases, examines the cold and warmth of seasonal rhythms, and observes the auspiciousness or inauspiciousness of people's diseases. It governs that when all things flourish, they all flourish; when diseases arise, they all arise. This belongs to the root and branch of Heaven and Earth's Qi dynamics. Speaking of the root and branch of the body: the Zang organs are the root, and the Fu organs are the branch. The Zang organs govern the interior and blood; the Fu organs belong to the exterior and Qi. This governs the prosperity or decline of Zang-Fu Qi and Blood, determines the strength of sinews, marrow, bones, and brain, manages the depth of diseases, and dictates longevity or premature death. This belongs to the root and branch of Yin and Yang in the body. Speaking of the root and branch of diseases: the initial onset is the root, and subsequent transmission/progression is the branch; furthermore, primordial Qi is the root, and pathogenic Qi is the branch. This governs diseases of cold/heat, interior/exterior, and urgency/slowness, corresponding to formulas for sweating, purging, tonifying, draining, and harmonizing. For any practitioner, treating the root first and the branch second is indeed appropriate; however, treating the branch first and the root second causes pathogenic Qi to proliferate and the disease to worsen. It is also said that in slow cases, treat the root; in urgent cases, treat the branch. For example, if one first develops an abscess/carbuncle, and subsequently suffers from diarrhea, vomiting, and poor appetite, one should adopt the method of abandoning the root to treat the branch. Wait until diarrhea stops, vomiting ceases, and appetite returns before treating the abscess/carbuncle again. Other cases follow this pattern. Indiscriminate application of tonification and purgation leads to errors in both aspects; this pertains to the root and branch of the relationship between pathogenic and healthy Qi in diseases.

It is also stated that Yang transforms into Yin due to internal and external exposure to cold and cooling agents that suppress and attack.

Sores originating from Yang manifest as carbuncles (Yong), heat, excess, and pain. These originally belong to Yang syndromes which are easy to treat. However, patients often do not perceive them as serious, considering them minor ailments, and fail to seek treatment early. Instead, they suffer external wind-cold and internal injury from raw/cold foods. Or, physicians fail to provide supportive tonification and instead apply cooling compresses, aiming for internal resolution to please the patient. This often leads to the freezing congealing of Qi and Blood, damage to the Spleen and Stomach, preventing the sore toxin from expressing outwardly, causing it to invade inward. In such cases, many die incurably. If the sore transforms into Yin before the eleventh day, prior to suppuration, presenting flat against healthy skin, without pain or heat, soft and slow, with only clear thin fluid leaking from the pore, accompanied by no fever, fine and minute pulse, anorexia, and mental fatigue/drowsiness, the toxin has transformed inward. Even if True Yin is strong, if warming the middle and strengthening the Spleen fails to respond, there is less than one chance in a hundred of survival. If the transformation occurs after the fifteenth day, during suppuration, when the toxic vapor is already attempting to express outwardly, but improper care or consumption of cold foods suddenly causes a shift to Yin, urgently administer Tuoli Wenzhong Tang (Support Interior and Warm Middle Decoction) or Shierwei Yigong San (Twelve-Ingredient Extraordinary Merit Powder). For mild cases, use Shiquan Dabu Tang (Complete and Great Tonification Decoction), doubling the dosage of Renshen (Ginseng), Baizhu (Atractylodes Macrocephala), Guizhi (Cinnamon Twig), and Fuzi (Prepared Aconite Root) to rescue the patient. Auspicious signs include the sore becoming hot and painful, pus discharge, warm body, rising pulse, and improved appetite. Since sores originally originate from Yang, many patients survive.

Who would expect Yin to transform into Yang? Throughout the course, support is provided with acrid-hot herbs, distinguishing true from false appearances, and investigating the principles of Yin and Yang.

Sores originating from Yin manifest as ulcers (Ju), cold, hardness, and deficiency. These originally belong to difficult-to-treat Yin syndromes. Patients are aware of their condition. To ensure survival, they might intentionally consume acrid-aromatic wines or large doses of hot medicines to assist themselves. Physicians, hoping for high swelling, heat, and suppuration at the site, apply hot compresses to encourage development. Thus, the sore receives intense heat from the medicine, transforming Yin into Yang. Although the sore exhibits slight swelling, heat, pain, and pus, its shape never resembles the vibrant redness of true Yang, nor does it produce genuine thick yellow pus. Such sores soon revert to Yin. Since sores originally stem from Yin, patients often die. In such cases, if the patient remains calm and trusts the physician, and the physician possesses profound insight and appropriate methods, achieving harmony between internal and external treatments, occasionally hitting the mark, there may be a chance of survival—one or two in ten. The urgency is like rescuing from fire or drowning; action must not be delayed. It is as precarious as walking on ice or near an abyss; caution must be absolute. If life is still not saved under these conditions, it is truly destiny.

Given the differing theories of needle workers, how could there be no detailed accounts of thread medicines?

Once a sore toxin has formed, it should be supported to generate pus; once pus has formed, it should be drained with a needle. This is a universally accepted good practice. One must verify the maturity, depth, and location before needling. If the swelling is high and soft, originating in muscle, and the pus is mature, needle only 4-5 fen deep. If the swelling is low and hard, originating in sinews and vessels, and the pus is mature, needle only 6-7 fen deep. If the swelling is flat with unchanged skin color, the toxic vapor adheres to the bone; for mature pus, needle deeply, about one cun, to reach the pus. Light pressure causing intense heat and pain indicates pus that is shallow and thick. Heavy pressure causing slight heat and pain indicates pus that is deep and thin. Depression that does not rebound indicates immature pus; softness that rebounds indicates mature pus. Uniform hardness without pain indicates no pus (either no pus or blood stasis); uniform softness without pain indicates pus (either pus or damp fluid). Where there is pus, one must needle; the opening should face downward. If needling immature pus, Qi and Blood leak, hindering pus formation. If mature pus is not drained, rotting deepens, and healing is delayed. If the pus is deep but needling is shallow, internal pus remains while external blood leaks. If the pus is shallow but needling is deep, internal pus exits but healthy flesh is damaged. For those with deficient primordial Qi, tonify first, then drain the pus, ensuring all symptoms recede. Regarding Qi Ying (Qi Goiter), characterized by soft, non-painful swelling, and Xue Ying (Blood Goiter), characterized by internal lump formation, or chronic stubborn toxins with decaying skin, purple flesh, hard roots, and surrounding red filaments, as well as tubercles that gradually enlarge, hurt, and decay: these four conditions must not be lightly pierced with needles or knives. Reckless use leads to uncontrollable hemorrhage and immediate danger. The subtlety of needling lies in the pus exiting silently without sensation. As for goiters, scrofula (Luoli), various hemorrhoids, fistulas, carbuncles, and hard stubborn sores, these conditions cannot achieve timely results without the efficacy of thread medicines. Thread medicines comprise five or six types, too numerous to list here. Corresponding ones are attached to respective chapters for selection, hence omitted in this section. Those who use them should do so skillfully.

Decoctions, powders, pills, and elixirs must hit the target upon release; Shen, Sheng, Gong, Qiao are indeed the keys for learners.

A skilled physician uses formulas like a skilled general uses troops. One adept in water navigates seas and waves; one adept on land crosses mountains and vines. Odd and even formations inspire movement; paths involve sinking and drilling. Weak positions defend; strong positions engage enemies. This is the great method of generals utilizing troops. Physicians should emulate this principle. The key lies in knowing the patient's strength, recognizing the disease's interior/exterior nature, investigating its depth, and observing the timing's favorability. Then, determine if sweating, purging, vomiting, or descending methods are suitable, or if harmonizing or tonifying is appropriate. Know which decoction excels at sweating, which powder at purging, which pill at harmonizing, and which elixir at tonifying. Apply the formula according to the disease, like an arrow striking the target upon release, winning the battle, and thus curing the disease. This is the great method of physicians mastering and applying formulas. Furthermore, Observation, Listening/Smelling, Inquiry, and Palpation correspond to Shen, Sheng, Gong, and Qiao. Observe form to understand spirit; listen to voice to clarify sagacity; inquire into origins to gain craftsmanship; palpate pulse to continue skill. These four are the standard guidelines for beginners.

Regarding thousands of prescriptions and hundreds of diseases, it is hard to exhaustively discuss their merits and faults.

Prescriptions need not be numerous; resonance brings efficacy. Diseases need not be complex; comprehension brings clarity. Without resonance, prescriptions are ineffective; without comprehension, diseases remain obscure, like distant acquaintances or barren lands. How can one rely on them? Thus, medicine not matching the disease, or the disease not matching the medicine, is evidence of this failure.

Treatment relies on flexible methods, valuing careful examination.

I have heard that in times of peace, activities differed from turbulent times; work and rest patterns varied. Previously, diseases originated externally; now, they originate internally. Ancient times saw more excess conditions, requiring dispersing and ventilating formulas; modern times see more deficiency conditions, requiring nourishing and tonifying methods. If physicians do not understand the past to know the present, and apply treatments indiscriminately, it will likely lead to premature death.

Application must be appropriate; only then can a physician be called excellent. Though these words may seem crude, they serve as an outline for future learners.