寒伤形，热伤气。气伤痛，形伤肿。故先痛而后肿者，气伤形；先肿而后痛者，形伤气也。（《素问》。）
病在阳者命曰风，在阴者命曰痹，阴阳俱病命曰风痹。病有形而不痛者，阳之类也。无形而痛者，阴之
类也。（阴痹者，按之不可得。）无形而痛者，其阳完而阴伤之也，急治其阴，无
攻其阳。有形而不痛者，其阴完而阳伤之也，急治其阳，无攻其阴。阴阳俱动，乍有形，乍无形，加以
烦心，命曰阴胜其阳，此谓不表不里，其形不久。（《灵枢》。）
形盛脉细，少气不足以息者危。形瘦脉大，胸中多气者死，形气相得者生。（平人气胜形者寿。病而形肉
脱，气胜形者死，形胜气者危。）目眶内陷者死。皮肤着（入声，枯也。）者死。脱肉，身不
去者死。形肉已脱，九候虽调，犹死。若夫急虚身中，譬如堕溺，不可为期，其形肉虽不脱，犹死也。（病而
气胜形者，喘息低昂，抬肩撼胸。）
形弱气虚死。形气有余，脉气不足死。脉气有余，形气不足生。
气盛身寒，（恶寒。）得之伤寒。气虚身热，（恶热。）得之伤暑。谷入多而气少者，得之有所脱血，湿居下也。
谷入少而气多者，邪在胃及与肺也。脉小血多者，饮中热也。脉大血少者，脉有风气，水浆不入也。（《素问》。）
形气不足，病气有余，是邪胜也，急当泻之。形气有余。病气不足，急当补之。形气不足，病气不足，此
阴阳俱不足也。不可刺之，刺之重不足，则阴阳俱竭，血气皆尽，五脏空虚，筋骨髓枯，老者灭绝，壮者
不复矣。形气有余，病气有余，此阴阳俱有余也。急泻其邪，调其虚实。李东垣曰∶
病来潮作之时，病气精神增添者，是为病气有余，乃邪气胜也，急泻之。病来潮作之时，神气困弱者，为病
气不足，乃真气不足也，急补之。不问形气有余不足，只从病气上分别补泻。形谓皮肉筋骨血脉也，气谓
口鼻气息也。（东垣释《内经》，出《内外伤辨》。）
Cold pathogenic factors damage the *xing* (physical structure/body), while heat pathogenic factors damage *qi* (vital energy). Damage to qi leads to pain, and damage to xing leads to swelling. Therefore, if pain occurs first followed by swelling, it indicates that qi has damaged xing; if swelling occurs first followed by pain, it indicates that xing has damaged qi. (From *Suwen*.)
Diseases located in the Yang aspect are termed *Feng* (Wind), those in the Yin aspect are termed *Bi* (Obstruction/Syndrome), and those affecting both Yin and Yang are termed *Feng-Bi*. Diseases with physical manifestations but without pain belong to the category of Yang. Diseases without physical manifestations but with pain belong to the category of Yin. (In cases of Yin Bi, pressing on the area yields no tenderness.) When there is no physical manifestation but there is pain, it means Yang is intact while Yin is injured; urgently treat Yin, do not attack Yang. When there is a physical manifestation but no pain, it means Yin is intact while Yang is injured; urgently treat Yang, do not attack Yin. When both Yin and Yang fluctuate abnormally, alternating between having physical manifestations and being formless, accompanied by vexation and heart discomfort, this is termed "Yin surpassing Yang." This condition is described as neither exterior nor interior, and the prognosis is poor, with life expectancy short. (From *Lingshu*.)
If the body is robust but the pulse is thin, and there is shortness of breath insufficient for respiration, the condition is critical. If the body is emaciated but the pulse is large, and there is excessive Qi sensation in the chest, death ensues. If the body and Qi are in harmony, survival is indicated. (Normally, individuals whose Qi exceeds their physical form live long. In disease, if muscle wasting occurs and Qi still exceeds the form, death ensues; if the form remains but Qi is deficient, the condition is critical.) Sunken eye sockets indicate death. Skin that is dry and adheres tightly to the bone indicates death. Severe muscle wasting with a stiff body unable to move indicates death. If the physical flesh and muscles have already wasted away, even if the pulses at all nine positions are harmonious, death still ensues. In cases of sudden severe deficiency where the pathogen strikes the body suddenly, like falling into water or drowning, the course cannot be predicted; even if the flesh has not completely wasted away, death ensues. (When Qi exceeds the form in disease, it manifests as loud breathing with varying pitch, lifting shoulders and heaving the chest.)
If the form is weak and Qi is deficient, death ensues. If the form and Qi are abundant but the pulse Qi is deficient, death ensues. If the pulse Qi is abundant but the form and Qi are deficient, survival is indicated.
If Qi is abundant but the body feels cold (aversion to cold), it results from Cold damage. If Qi is deficient but the body feels hot (aversion to heat), it results from Summerheat damage. If food intake is high but Qi is low, it results from blood loss or Dampness residing in the lower jiao. If food intake is low but Qi seems high, the pathogen is in the Stomach and Lungs. If the pulse is small but blood volume is high, it indicates Heat within fluid retention. If the pulse is large but blood volume is low, it indicates Wind pathogen in the vessels and inability to ingest fluids. (From *Suwen*.)
If the form and Qi are deficient, but the pathogenic Qi is abundant, this indicates excess of evil; urgently apply draining methods. If the form and Qi are abundant, but the pathogenic Qi is deficient, urgently apply tonifying methods. If both the form/Qi and the pathogenic Qi are deficient, this indicates deficiency of both Yin and Yang. Acupuncture should not be used; if needled, it will cause further deficiency, leading to exhaustion of both Yin and Yang, depletion of blood and Qi, emptiness of the five Zang organs, and withering of sinews, bones, and marrow. The elderly will perish, and the strong will not recover. If both the form/Qi and the pathogenic Qi are abundant, this indicates excess of both Yin and Yang. Urgently drain the evil pathogen and regulate deficiency and excess. Li Dongyuan stated: When the disease flares up, if the patient's spirit and vitality increase, this is excess of pathogenic Qi, indicating dominance of evil pathogen; urgently drain it. When the disease flares up, if the spirit and Qi are fatigued and weak, this is deficiency of pathogenic Qi, indicating deficiency of true Qi; urgently tonify it. Regardless of whether the form and Qi are abundant or deficient, distinguish tonification and drainage solely based on the pathogenic Qi. "Form" refers to skin, flesh, sinews, bones, and vessels; "Qi" refers to the breath from mouth and nose. (Li Dongyuan's interpretation of *Neijing*, from *Bian Huo Lun*.)