凡勘伤寒。既明病所之表里。病状之寒热。尤必明病患之气血。病体之虚实。《内经》云。精气夺则虚。邪气
盛则实。窃思精赅血液而言。气赅阴阳而言。盛与衰为对待。不曰衰则虚。而曰夺则虚者。知其必有所劫夺。
而精血精液阴气阳气乃虚。劫夺者何。非情志内伤。即邪气外侵。故《经》曰邪之所凑。其气必虚者。盖谓
邪凑气分则伤气。邪凑血分则伤血。气血既伤。则正气必虚。医必求其所伤何邪而先去其病。病去则虚者亦生。
病留则实者亦死。虽在气血素虚者。既受邪气。如酷暑严寒。却为虚中夹实。但清其暑散其寒以去邪。邪
去则正自安。若不去其邪。而先补其虚。则病处愈实。未病处愈虚。以未病处之气血。皆挹而注于病处。此气
血因夺而虚之真理也。医可不深思其理而漫曰虚者补之乎。然间有因虚不能托邪者。亦须略佐补托。如仲景《伤寒
论》中。轻则佐草、枣。佐草、米。重则佐芍、草、枣。或佐参、草、枣之类是也。兹姑不具论。第论气血。气有
盛衰。盛则实。衰则虚。血有亏瘀。亏则虚。瘀则实。析而言之。有气虚。有气实。有血虚。有血实。有气血
皆虚。有气血皆实。有气虚血实。有气实血虚。有气真虚而血假实。
有血真实而气假虚。试举其要而述之。
大凡诊察伤寒病，既然已经明确了病位的表里、病状的寒热，尤其必须明确病患的气血状况以及病体的虚实状态。《黄帝内经》说：“精气被耗夺则表现为虚证，邪气强盛则表现为实证。”我私下思考，“精”涵盖血液而言，“气”涵盖阴阳而言。“盛”与“衰”是相对的概念，不称“衰”而称“夺”以表示虚，是因为知道必然有所劫夺，从而导致精血、精液、阴气、阳气出现虚损。所谓劫夺，是什么呢？不是情志内伤，就是邪气外侵。所以《内经》说：“邪气聚集的地方，正气必定虚弱。”这意思是说，邪气侵犯气分就会损伤气，邪气侵犯血分就会损伤血。气血既然受损，那么正气必然虚弱。医生必须探求是什么邪气造成了伤害，并首先去除病邪。病邪去除，那么虚弱的身体也能恢复生机；病邪留存，那么看似实证的患者也会死亡。即使是在气血本来就虚弱的人身上，一旦感受了邪气，比如酷暑或严寒，却属于虚中夹实（本虚标实）。但只要清除暑热、发散寒气以祛除邪气，邪气一去，正气自然安宁。如果不去除邪气，而先补益其虚损，那么患病部位会变得更加壅实，未患病的部位会变得更加虚弱，这是因为未病部位的气血都被吸引并灌注到患病部位去了。这就是气血因被劫夺而致虚的真理。医生能不深思其中的道理，就漫无边际地说“虚者补之”吗？然而间或有因为正气虚弱而不能托举驱散邪气的情况，也必须略微辅以补益托毒之法。如张仲景《伤寒论》中，轻症时辅助使用甘草、大枣，辅助使用甘草、粳米；重症时辅助使用白芍、甘草、大枣，或者辅助使用人参、甘草、大枣之类的方法。这里暂且不详细论述这些，只讨论气血问题。气有盛衰之分，盛则为实证，衰则为虚证；血有亏虚和瘀滞之别，亏虚则为虚证，瘀滞则为实证。细致分析来说，有气虚，有气实，有血虚，有血实，有气血皆虚，有气血皆实，有气虚血实，有气实血虚，有气真虚而血假实，有血真实而气假虚。试列举其主要内容并加以阐述。
In general, when examining Shanghan (Cold Damage diseases), after having clarified the exterior and interior locations of the disease and the cold or heat manifestations of the symptoms, one must particularly ascertain the Qi and Blood status of the patient and the deficiency or excess condition of the pathological body. The *Huangdi Neijing* (Yellow Emperor's Inner Canon) states: "When Jing Essence is depleted, it manifests as Deficiency; when Pathogenic factors are exuberant, it manifests as Excess." I have pondered that "Jing" encompasses Blood, while "Qi" encompasses Yin and Yang. "Exuberance" and "Decline" are contrasting concepts. It does not say "decline" but rather "depletion" to indicate Deficiency, implying that there must be a certain robbery or loss, leading to the deficiency of Jing Blood, Jing Fluids, Yin Qi, and Yang Qi. What constitutes this robbery? It is either internal injury due to emotional disturbances or external invasion by pathogenic factors. Thus, the Classics state: "Wherever pathogenic factors gather, the healthy Qi must be deficient." This means that when pathogens invade the Qi level, they damage Qi; when they invade the Blood level, they damage Blood. Once Qi and Blood are damaged, the Healthy Qi inevitably becomes deficient. The physician must determine which pathogen caused the injury and first eliminate the disease. If the disease is eliminated, even the deficient will recover vitality; if the disease remains, even those appearing in an Excess state may die. Even in individuals with inherently deficient Qi and Blood, once exposed to pathogens such as intense summer heat or severe cold, the condition becomes Deficiency with夹杂 Excess (Deficiency mixed with Excess). However, by clearing the summer heat and dispersing the cold to remove the pathogen, once the pathogen is gone, the Healthy Qi naturally settles. If one fails to remove the pathogen and instead tonifies the deficiency first, the affected area will become more Excess, while unaffected areas will become more deficient, because the Qi and Blood from unaffected areas are drawn and poured into the affected site. This is the fundamental truth regarding Qi and Blood becoming deficient due to depletion. Can physicians fail to deeply contemplate these principles and merely casually apply the rule "Tonify the Deficient"? Nevertheless, occasionally there are cases where deficiency prevents the expulsion of pathogens, requiring slight assistance with tonification and expulsion methods. For instance, in Zhang Zhongjing's *Shanghan Lun* (Treatise on Cold Damage), mild cases assist with Licorice Root and Jujube Fruit, or Licorice Root and Rice; severe cases assist with White Peony Root, Licorice Root, and Jujube Fruit, or Ginseng Root, Licorice Root, and Jujube Fruit, etc. These will not be discussed in detail here; we shall only discuss Qi and Blood. Qi has exuberance and decline; exuberance indicates Excess, decline indicates Deficiency. Blood has deficiency and stasis; deficiency indicates Deficiency, stasis indicates Excess. Analyzing in detail, there is Qi Deficiency, Qi Excess, Blood Deficiency, Blood Excess, simultaneous Qi and Blood Deficiency, simultaneous Qi and Blood Excess, Qi Deficiency with Blood Excess, Qi Excess with Blood Deficiency, True Qi Deficiency with False Blood Excess, and True Blood Excess with False Qi Deficiency. Let us list the essentials and elaborate upon them.