Library

Deficiency and collapse of Yin and Yang are distinguished by external causes and internal causes, and differ in terms of excessive dominance (Pian Sheng) and extreme depletion (Pian Jue).

If pathogenic factors invade the Yin aspect, resulting in cold extremities and a faint pulse nearly imperceptible, this indicates that excessive Yin is causing the Qi generating Yang to be on the verge of exhaustion internally.

If there is a desire for iced beverages, a desire to lie on cool ground, removing clothes and bedding, restlessness and unease, this signifies that Yin Cold is excessive internally while Yang is about to collapse externally; urgent treatment with Renshen (Ginseng Radix et Rhizoma), Fuzi (Aconiti Lateralis Radix Preparata), Ganjiang (Zingiberis Rhizoma), and Guizhi (Cinnamomi Ramulus) is required to rescue the condition.

If sweating fails to resolve the condition and the body becomes feverish instead, this indicates excessive Yang and internal exhaustion of Yin. For instance, in Yangming disease (disease of the Yangming channel), where there is fever and profuse sweating, urgent purgation is indicated, suitable for Dachengqi Tang (Major Order the Qi Decoction); this represents excessive Yang internally and external collapse of Yin fluids. These are cases of Yin-Yang imbalance and extreme depletion due to external causes.

Regarding internal causes of Yin and Yang: Yang is born from Yin, and Yin is born from Yang. "Yang born from Yin" means Yang Qi originates from Yin Essence; "Yin born from Yang" means Yin Essence is generated through the transformational power of Yang. This transformation refers to Yang Qi transforming the essence of food and drink to generate this essence. When Yin and Yang harmonize and mutually generate each other, one is considered a healthy person (Ping Ren). If solitary Yang cannot grow and isolated Yin cannot develop, it indicates that the vital mechanism of Yin and Yang is about to cease internally. The Nan Jing states: "Those whose Yang collapses see ghosts; those whose Yin collapses go blind." Generally, Yang collapse involves departure from the lower part upwards; Yin collapse involves departure from the upper part downwards. Therefore, those who go blind due to Yin collapse may still have their life prolonged slightly, whereas those who see ghosts due to Yang collapse will die within a few days.

The affliction of Yang collapse often stems from Yin deficiency. For example, in elderly people with cold feet and knees, this indicates that Yuan Qi (Primordial Qi) is gradually declining, with Yang about to fail at the lower part; treatments such as Shenfu Wan (Ginseng and Aconite Pill) or Banshu Wan (Half-Sulfur Pill) should be used to assist the generation of Yang. If Spleen and Stomach deficiency leads to failure in producing grain essence, or if excessive sexual activity daily damages Kidney Essence, or if worry and fear gradually deplete stored essence, or if mental toil daily consumes spirit and vitality, leading to daily decline of Yin Qi and impending external collapse of Yang, then practitioners of preventive treatment (Zhi Wei Bing) must recognize that Yin Essence deficiency is the precursor to Yang collapse and preemptively nourish Yin.

If one waits until Yang has already collapsed externally and uses Guizhi and Fuzi hoping to guide fire back to its source, without realizing that Yin Essence is the origin of Yang's generation, once this origin is severed, where can it return? Thus, using Guizhi and Fuzi to rescue Yang collapse applies to collapse due to external causes; using them for internal causes serves to assist declining Yang at the lower part. (Note: In cases of Yin deficiency leading to Yang collapse, Guizhi and Fuzi are not curative.) Hence, it is said that deficiency and collapse of Yin and Yang are distinguished by external and internal causes, and differ in excessive dominance and extreme depletion.