虚火二字,混淆已久,贻误最多,不可以不辨也。夫火有阴盛格阳之火,有阴虚火动
有纯属阴虚,似火非火之火。所谓阴盛格阳者,龙雷之火,得水愈燔,得热则散,内真寒而
外假热,真正之虚火也,补阳即消矣,有曰虚火宜补温,能除大热者,此之谓也。所谓阴虚
火动者,真水亏乏,邪火妄行,神魂躁动,内外枯热,是亦不得不谓之虚火,若补阳,则助
其热矣,有曰阳旺阴愈消,热增水益涸者,此之谓也。所谓似火非火者,原无外火销烁,止
以真阴亏竭,泉源断流,而致为干枯燥旱,是又不可不名为虚火,此则肾水大伤,非纯补真
阴莫济矣,有曰补阴以配阳者,此之谓也。
虚损之脉,凡甚急、甚数、甚细、甚弱、甚涩、甚滑、甚短、甚长、甚浮、甚沉、甚
紧、甚洪、甚实者,皆是其候。然阴阳之辨,则全以迟数二字,为损症之大关键,虽其迟数
中,又有浮、沉、大、小、之不同,要以阴虚脉数,阳虚脉迟,不可易也。大凡数脉不及六
至者,可治也。六至以上者,难治也。若数甚而再加弦紧细小,则百无一生矣。然脉数至极
多,有兼滑,但见其滑愈甚者,其死愈近,以决短期,万无或爽也。
迟不甚迟,而脉中有神者,治之甚易,可数剂取效也。迟败之极,而微弱无神者,死
在顷刻,虽大进温补,无能为力也。
阴虚脉数,阳虚脉迟,是固然矣,及病至危笃,亦有数之至而渐缓者,以阴脱尽而阳
也。又有迟之甚而转数者,以阳败极而阴亦渐散也。此不得视为佳兆,正死期之日促耳!
阴阳虽为对待,然世人劳损,毕竟阴虚脉数者居多,阳虚脉迟者恒少,所以但见脉数
,便须认定阴虚,断不容混。惟知愈虚则愈数,愈数则愈虚,而弱症思过半矣。
弦脉者,虚损最忌,又最多也。《脉经》谓之中虚,崔真人谓之土败。以余观之,亦
迟数,盖凡迟缓而弦者,其为中虚土败,不待言耳!若数中兼弦,则以水枯木燥,愈燥愈弦
,愈弦愈燥,并不关中土之病,即使木气燥极,亦致凌脾,究竟补水为主。而快脾等剂,断
不可用,毫厘之失,何啻千里之差!
世人右尺虚者极多,粗工不察,动云补火,不知火上浮则右尺必虚,不定属肾寒也。
若不加详审,而遽投温热,鲜不致误矣。
The term "deficiency fire" (Xu Huo, deficiency fire) has been confused for a long time and has caused the most errors in treatment; it must not be left unclarified.
Fire can be categorized into three types: fire due to extreme yin excess repelling yang outward (true cold with false heat), fire moving due to yin deficiency, and fire that is purely due to yin deficiency, appearing like fire but not being true fire.
The so-called "fire due to yin excess repelling yang" refers to Dragon and Thunder Fire (Long Lei Zhi Huo, referring to the rebellious movement of Mingmen fire in the lower jiao). It burns more fiercely when meeting water and dissipates when meeting heat. It presents as true cold internally and false heat externally. This is true deficiency fire, which can be resolved by tonifying yang. When it is said that "deficiency fire should be treated with warming tonification to eliminate great heat," this is what is meant.
The so-called "fire moving due to yin deficiency" occurs when True Water (Zhen Shui, referring to Kidney Yin/fluids) is depleted, allowing pathogenic fire to act recklessly. The spirit and soul become agitated, and both interior and exterior present with dryness and heat. This also must be called deficiency fire. If one were to tonify yang, it would exacerbate the heat. When it is said that "when yang is vigorous, yin is further consumed; when heat increases, water sources are further dried up," this is what is meant.
The so-called "appearing like fire but not fire" implies that there is no external fire consuming fluids. Instead, it is caused by the exhaustion of True Yin, where the source dries up like a broken spring, leading to dryness and aridity. This too must be named deficiency fire. In this case, Kidney Water is severely injured, and only pure tonification of True Yin can save the patient. When it is said that "tonifying yin to harmonize with yang," this is what is meant.
Regarding the pulse of consumptive diseases (Xu Sun, wasting-thirst or chronic deficiency conditions), any pulse that is extremely rapid (Ji), frequent (Shu, rapid), thin (Xi), weak (Ruo), choppy (Se), slippery (Hua), short (Duan), long (Chang), floating (Fu), deep (Chen), tight (Jin), surging (Hong), or full (Shi) are all signs of such conditions.
However, the differentiation between yin and yang relies entirely on the two characters "slow" (Chi) and "rapid" (Shu), which are the key points for consumptive diseases. Although within these slow and rapid pulses, there are variations of floating, deep, large, and small, the general rule remains: yin deficiency manifests as a rapid pulse, and yang deficiency manifests as a slow pulse. This is immutable.
Generally, if the pulse rate is less than six beats per respiration cycle (one respiration cycle typically corresponds to 4-5 beats in normal conditions; 6+ indicates tachycardia), it is treatable. If it exceeds six beats per respiration cycle, it is difficult to treat. If the pulse is extremely rapid and additionally wiry (Xian), tight, thin, or small, there is virtually no chance of survival.
However, when the pulse is extremely rapid, it often accompanies a slippery quality. The more pronounced the slipperiness, the closer death is, allowing for an accurate prediction of the time of death without error.
If the pulse is slow but not excessively so, and possesses "spirit" (Shen, vitality/resilience in the pulse), treatment is very easy, and efficacy can be expected after a few doses. If the pulse is extremely slow and degenerated, weak, and devoid of spirit, death is imminent. Even with aggressive warming and tonification, there is nothing that can be done.
While it is true that yin deficiency presents with a rapid pulse and yang deficiency with a slow pulse, in critical stages, a pulse that is extremely rapid may gradually slow down because yin has completely exhausted and yang floats away (isolated yang floating outward). Conversely, a pulse that is extremely slow may turn rapid because yang has failed to the extreme and yin gradually scatters. These should not be viewed as good omens; rather, they indicate an approaching time of death.
Although yin and yang are opposing forces, among people suffering from labor-induced consumption, those with yin deficiency and rapid pulses are far more common than those with yang deficiency and slow pulses. Therefore, whenever a rapid pulse is seen, it must be identified as yin deficiency, and confusion is not permitted. Only by understanding that "the more deficient, the more rapid the pulse; the more rapid the pulse, the more deficient the condition," does one grasp half of the principles of treating weak conditions.
The wiry pulse (Xian Mai) is the most taboo and yet most common in consumptive diseases. *Mai Jing* (Pulse Classic) states it indicates middle jiao deficiency, and Cui Zhenren calls it earth failure. In my view, one must still look at whether it is slow or rapid. If it is slow and wiry, it is undoubtedly middle jiao deficiency and earth failure. If it is rapid and wiry, it is due to water exhaustion and wood dryness. The drier it becomes, the more wiry; the more wiry, the drier. This is not related to the disease of the central earth (Spleen/Stomach). Even if Wood qi is extremely dry and invades Spleen, the primary treatment must be to nourish water (Kidney Yin). Formulas that accelerate Spleen function (Kuai Pi) must absolutely not be used. A mistake of a hair's breadth results in a difference of a thousand miles.
Many people have a deficient Right Chi (Right Cun-Guan-Chi position, specifically Chi position, which monitors Kidney Yang/Mingmen) pulse. Unskilled physicians, failing to examine carefully, often claim the need to tonify fire (warm Kidney Yang). They do not realize that when fire floats upward (deficient yang floating upward), the Right Chi pulse will necessarily appear empty, which does not necessarily belong to Kidney Cold. Without detailed examination, rashly administering warming and hot substances rarely fails to cause misdiagnosis and harm.