Library

After three days of contracting exogenous wind-cold pathogenic factors, the grain is digested and water metabolism returns to normal; when the pathogenic factor transmits to the interior, thirst will then occur. Those suffering from endogenous injury due to irregular diet, overwork, or chronic illness will definitely not experience thirst, because the pathogenic factor resides in the blood vessels accompanied by dampness, hence no thirst. However, those initially injured heavily by overwork affecting their physical constitution or by irregular diet will certainly experience thirst, because excessive heart fire attacks lung metal upwards, causing thirst. Furthermore, differentiation should be made as follows: although the patient desires to drink water, it should be given slowly and in small amounts. One must not indulge the desire to drink excessively, for fear that excessive water intake rushing downwards will further weaken stomach qi. Mild cases may result in distension, while severe cases may lead to transmission and other diseases, inevitably causing recurrent restlessness and disturbance, discomfort of the hundred vessels, worsening symptoms at night, inability to sleep peacefully, all of which must be considered in advance.

Above differentiates between thirst and no thirst.

Zhang Zhongjing's *Treatise on Cold Damage* states that patients with wind-stroke can eat, and those with cold-damage can also eat; both conditions present with a neutral mouth sensation and no aversion to food. In contrast, the three conditions of injury from overwork, irregular diet, and inappropriate temperature exposure all result in aversion to food, loss of taste perception for the five flavors, and ignorance of the taste of grains. This single differentiation is sufficient to distinguish between the two syndromes of excess (external) and deficiency (internal). Although cold-damage patients can eat and are not averse to food, having a neutral mouth and perceiving the five flavors and grain tastes, this is because there is no internal injury syndrome; thus, heart and spleen qi are harmonious, allowing them to perceive the flavors of grains.

Above differentiates external injuries where there is no aversion to food; whereas the three conditions of overwork, irregular diet, and inappropriate temperature exposure all cause aversion to food.

In ancient times, perfect men explored the transformations of yin and yang and investigated the boundaries of life and death. The *Neijing* they authored entirely emphasizes that humans rely on stomach qi as the foundation. Essentially, humans derive life from the qi of water and grain. What is called clear qi, Ying qi (nutritive qi), Wei qi (defensive qi), and spring-rising qi are all alternative names for stomach qi. The stomach is the sea of water and grain. When food enters the stomach, its essence spreads and accumulates, transmitting upwards to the spleen. The spleen disperses fine essences, sending them upwards to the lung. The lung regulates water passages, transmitting downwards to the bladder. Water and essences distribute throughout the body, meridians run parallel, conforming to the four seasons and the yin-yang of the five zang organs, establishing the norm. If diet is irregular or temperature exposure is inappropriate, the spleen and kidney are damaged. Joy, anger, sorrow, fear, and overwork deplete yuan qi (original qi). Once spleen and stomach qi are weak and yuan qi is insufficient, heart fire becomes solitary and flourishing. Heart fire is also known as yin fire, originating from the lower jiao, connected to the heart, but since the heart does not issue commands, ministerial fire acts on its behalf. Ministerial fire is the fire of the pericardium in the lower jiao, a thief of yuan qi. Fire and yuan qi cannot coexist; when one prevails, the other declines. Spleen and stomach qi deficiency causes qi to flow downward into the kidney, allowing liver yin fire to invade the earth position (spleen/stomach). Therefore, in spleen and stomach disorders, initially there is qi rebellion with panting, body heat, and irritability, a flooding and large pulse, headache, or persistent thirst, and skin unable to withstand wind-cold, leading to alternating chills and fever. Generally, because yin fire rushes upward, there is qi rebellion with panting, body heat and irritability, headache, thirst, and a flooding pulse. Spleen and stomach qi flows downward, preventing grain qi from ascending; this means the command of growth does not operate, and there is no yang to protect Ying and Wei qi. Unable to withstand wind-cold, wind-heat arises. All these are caused by insufficiency of spleen and stomach qi. However, although the appearance resembles exogenous wind-cold syndromes, the mechanism differs. Endogenous injury to the spleen and stomach damages qi (internal); exogenous wind-cold damages the form (external). Injury to the exterior constitutes excess, treated by purging; injury to the interior constitutes deficiency, treated by tonifying. Treatments such as purgation, emesis, and harsh reduction belong to purging methods; warm, harmonizing, regulating, and nourishing methods belong to tonifying methods. If an endogenous deficiency disease is mistaken for an exogenous excess disease and treated with purging, the deficiency will become more deficient. The *Nan Jing* states: "Reinforce the excess and empty the deficiency," damaging the deficient and benefiting the excess. Such deaths are caused by the physician. One must only use sweet-warm formulas to tonify the middle and raise yang, and sweet-cool herbs to clear fire, and the disease will heal. The *Neijing* says: "For fatigue, use warmth; for depletion, use warmth." Warmth can eliminate great heat. Bitter-cold herbs that drain stomach qi are strictly contraindicated. Now, we establish Bu Zhong Yi Qi Tang (Tonify the Middle and Augment the Qi Decoction) as the principal prescription.